serial: ns16550: Fix pointer type mismatch

serial_out_dynamic() takes a u8* addr and uses it for 8-bit or 32-bit
accesses, depending on the value of plat->reg_width. This results in a
pointer type mismatch that the compiler may even turn into an error:

drivers/serial/ns16550.c: In function ‘serial_out_dynamic’:
drivers/serial/ns16550.c:115:42: error: passing argument 1 of ‘out_be32’ from incompatible pointer type [-Wincompatible-pointer-types]
  115 |                                 out_be32(addr, value);
      |                                          ^~~~
      |                                          |
      |                                          u8 * {aka unsigned char *}

This error was observed on PowerPC.

Signed-off-by: J. Neuschäfer <j.ne@posteo.net>
diff --git a/drivers/serial/ns16550.c b/drivers/serial/ns16550.c
index 0e267d0..7e460f6 100644
--- a/drivers/serial/ns16550.c
+++ b/drivers/serial/ns16550.c
@@ -112,9 +112,9 @@
 	} else if (plat->reg_width == 4) {
 		if (plat->flags & NS16550_FLAG_ENDIAN) {
 			if (plat->flags & NS16550_FLAG_BE)
-				out_be32(addr, value);
+				out_be32((u32 *)addr, value);
 			else
-				out_le32(addr, value);
+				out_le32((u32 *)addr, value);
 		} else {
 			writel(value, addr);
 		}
@@ -132,9 +132,9 @@
 	} else if (plat->reg_width == 4) {
 		if (plat->flags & NS16550_FLAG_ENDIAN) {
 			if (plat->flags & NS16550_FLAG_BE)
-				return in_be32(addr);
+				return in_be32((u32 *)addr);
 			else
-				return in_le32(addr);
+				return in_le32((u32 *)addr);
 		} else {
 			return readl(addr);
 		}