serial: Rename ns16550 functions to lower case

Lower case should be used for function names. Update this driver and its
callers accordingly.

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

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
diff --git a/board/Arcturus/ucp1020/spl_minimal.c b/board/Arcturus/ucp1020/spl_minimal.c
index 38d84af..90abec9 100644
--- a/board/Arcturus/ucp1020/spl_minimal.c
+++ b/board/Arcturus/ucp1020/spl_minimal.c
@@ -34,7 +34,7 @@
 	plat_ratio >>= 1;
 	gd->bus_clk = CONFIG_SYS_CLK_FREQ * plat_ratio;
 
-	NS16550_init((struct ns16550 *)CONFIG_SYS_NS16550_COM1,
+	ns16550_init((struct ns16550 *)CONFIG_SYS_NS16550_COM1,
 		     gd->bus_clk / 16 / CONFIG_BAUDRATE);
 
 	puts("\nNAND boot... ");
@@ -55,9 +55,9 @@
 void putc(char c)
 {
 	if (c == '\n')
-		NS16550_putc((struct ns16550 *)CONFIG_SYS_NS16550_COM1, '\r');
+		ns16550_putc((struct ns16550 *)CONFIG_SYS_NS16550_COM1, '\r');
 
-	NS16550_putc((struct ns16550 *)CONFIG_SYS_NS16550_COM1, c);
+	ns16550_putc((struct ns16550 *)CONFIG_SYS_NS16550_COM1, c);
 }
 
 void puts(const char *str)