Blackfin: serial: convert to bfin_{read,write} helpers

Since the serial struct declares the sizes for us, no need to hardcode
them in the accessor functions.  Let the bfin_{read,write} helpers do
it for us.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/arch/blackfin/cpu/initcode.c b/arch/blackfin/cpu/initcode.c
index 917b7f9..fb3a101 100644
--- a/arch/blackfin/cpu/initcode.c
+++ b/arch/blackfin/cpu/initcode.c
@@ -19,6 +19,8 @@
 #include <asm/mach-common/bits/pll.h>
 #include <asm/mach-common/bits/uart.h>
 
+#define BUG() while (1) { asm volatile("emuexcpt;"); }
+
 #include "serial.h"
 
 __attribute__((always_inline))