x86, setup: reorganize the early console setup

Separate early_serial_console from tty.c

This allows for reuse of
early_serial_console.c/string.c/printf.c/cmdline.c in boot/compressed/.

-v2: according to hpa, don't include string.c etc
-v3: compressed/misc.c must have early_serial_base as static, so move it back to tty.c
     for setup code

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <4C568D2B.205@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

arch/x86/boot/printf.c

@@ -34,7 +34,7 @@ static int skip_atoi(const char **s)
 #define SMALL	32		/* Must be 32 == 0x20 */
 #define SPECIAL	64		/* 0x */
 
-#define do_div(n,base) ({ \
+#define __do_div(n, base) ({ \
 int __res; \
 __res = ((unsigned long) n) % (unsigned) base; \
 n = ((unsigned long) n) / (unsigned) base; \
@@ -83,7 +83,7 @@ static char *number(char *str, long num, int base, int size, int precision,
 		tmp[i++] = '0';
 	else
 		while (num != 0)
-			tmp[i++] = (digits[do_div(num, base)] | locase);
+			tmp[i++] = (digits[__do_div(num, base)] | locase);
 	if (i > precision)
 		precision = i;
 	size -= precision;