kbuild: Remove uncmd_spl logic

At this point in the conversion there should be no need to have logic to
disable some symbol during the SPL build as all symbols should have an
SPL counterpart.

The main real changes done here are that we now must make proper use of
CONFIG_IS_ENABLED(DM_SERIAL) rather than many of the odd tricks we
developed prior to CONFIG_IS_ENABLED() being available.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/drivers/serial/serial_pl01x.c b/drivers/serial/serial_pl01x.c
index 7449e9b..f546835 100644
--- a/drivers/serial/serial_pl01x.c
+++ b/drivers/serial/serial_pl01x.c
@@ -27,8 +27,7 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
-#ifndef CONFIG_DM_SERIAL
-
+#if !CONFIG_IS_ENABLED(DM_SERIAL)
 static volatile unsigned char *const port[] = CFG_PL01x_PORTS;
 static enum pl01x_type pl01x_type __section(".data");
 static struct pl01x_regs *base_regs __section(".data");
@@ -186,7 +185,7 @@
 	return 0;
 }
 
-#ifndef CONFIG_DM_SERIAL
+#if !CONFIG_IS_ENABLED(DM_SERIAL)
 static void pl01x_serial_init_baud(int baudrate)
 {
 	int clock = 0;
@@ -273,11 +272,7 @@
 {
 	return &pl01x_serial_drv;
 }
-
-#endif /* nCONFIG_DM_SERIAL */
-
-#ifdef CONFIG_DM_SERIAL
-
+#else
 int pl01x_serial_setbrg(struct udevice *dev, int baudrate)
 {
 	struct pl01x_serial_plat *plat = dev_get_plat(dev);