serial: Update NS16550_t and struct NS16550

Typedefs should not be used in U-Boot and structs should be lower case.
Update the code to use struct ns16550 consistently.

Put a header guard on the file while we are here.

Signed-off-by: Simon Glass <sjg@chromium.org>

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
diff --git a/arch/arm/mach-davinci/da850_lowlevel.c b/arch/arm/mach-davinci/da850_lowlevel.c
index 07bf19b..6994ded 100644
--- a/arch/arm/mach-davinci/da850_lowlevel.c
+++ b/arch/arm/mach-davinci/da850_lowlevel.c
@@ -290,8 +290,8 @@
 	board_gpio_init();
 
 #if !CONFIG_IS_ENABLED(DM_SERIAL)
-	NS16550_init((NS16550_t)(CONFIG_SYS_NS16550_COM1),
-			CONFIG_SYS_NS16550_CLK / 16 / CONFIG_BAUDRATE);
+	NS16550_init((struct ns16550 *)(CONFIG_SYS_NS16550_COM1),
+		     CONFIG_SYS_NS16550_CLK / 16 / CONFIG_BAUDRATE);
 #endif
 	/*
 	 * Fix Power and Emulation Management Register
diff --git a/arch/arm/mach-davinci/spl.c b/arch/arm/mach-davinci/spl.c
index 5fea935..3c8330b 100644
--- a/arch/arm/mach-davinci/spl.c
+++ b/arch/arm/mach-davinci/spl.c
@@ -27,9 +27,9 @@
 void putc(char c)
 {
 	if (c == '\n')
-		NS16550_putc((NS16550_t)(CONFIG_SYS_NS16550_COM1), '\r');
+		NS16550_putc((struct ns16550 *)(CONFIG_SYS_NS16550_COM1), '\r');
 
-	NS16550_putc((NS16550_t)(CONFIG_SYS_NS16550_COM1), c);
+	NS16550_putc((struct ns16550 *)(CONFIG_SYS_NS16550_COM1), c);
 }
 #endif /* CONFIG_SPL_LIBCOMMON_SUPPORT */
 
diff --git a/arch/arm/mach-keystone/init.c b/arch/arm/mach-keystone/init.c
index 88e8912..f4edaaa 100644
--- a/arch/arm/mach-keystone/init.c
+++ b/arch/arm/mach-keystone/init.c
@@ -185,7 +185,7 @@
 	 * driver doesn't handle this.
 	 */
 #ifndef CONFIG_DM_SERIAL
-	NS16550_init((NS16550_t)(CONFIG_SYS_NS16550_COM2),
+	NS16550_init((struct ns16550 *)(CONFIG_SYS_NS16550_COM2),
 		     CONFIG_SYS_NS16550_CLK / 16 / CONFIG_BAUDRATE);
 #endif
 
diff --git a/arch/x86/cpu/apollolake/uart.c b/arch/x86/cpu/apollolake/uart.c
index 26aef65..8e6dfdb 100644
--- a/arch/x86/cpu/apollolake/uart.c
+++ b/arch/x86/cpu/apollolake/uart.c
@@ -127,7 +127,7 @@
 	.id	= UCLASS_SERIAL,
 	.of_match = apl_ns16550_serial_ids,
 	.plat_auto	= sizeof(struct ns16550_plat),
-	.priv_auto	= sizeof(struct NS16550),
+	.priv_auto	= sizeof(struct ns16550),
 	.ops	= &ns16550_serial_ops,
 	.of_to_plat = apl_ns16550_of_to_plat,
 	.probe = apl_ns16550_probe,
diff --git a/arch/x86/cpu/slimbootloader/serial.c b/arch/x86/cpu/slimbootloader/serial.c
index 5d89632..ebbd2c5 100644
--- a/arch/x86/cpu/slimbootloader/serial.c
+++ b/arch/x86/cpu/slimbootloader/serial.c
@@ -59,7 +59,7 @@
 	.of_match = slimbootloader_serial_ids,
 	.of_to_plat = slimbootloader_serial_of_to_plat,
 	.plat_auto	= sizeof(struct ns16550_plat),
-	.priv_auto	= sizeof(struct NS16550),
+	.priv_auto	= sizeof(struct ns16550),
 	.probe	= ns16550_serial_probe,
 	.ops	= &ns16550_serial_ops,
 };