arch/x86: Fix most of remaining issues detected by checkpatch

Fix the following errors and warnings detected by checkpatch.pl:

ERROR: do not use assignment in if condition
ERROR: trailing statements should be on next line
ERROR: Macros with complex values should be enclosed in parentheses
ERROR: switch and case should be at the same indent
WARNING: char * array declaration might be better as static const
WARNING: else is not generally useful after a break or return
WARNING: storage class should be at the beginning of the declaration
WARNING: void function return statements are not generally useful
WARNING: break is not useful after a goto or return
WARNING: Single statement macros should not use a do {} while (0) loop
WARNING: sizeof *t should be sizeof(*t)
WARNING: Comparisons should place the constant on the right side of the test

TEST=Build and run on Galileo Gen2

Change-Id: I39d49790c5eaeedec5051e1fab0b1279275f6e7f
Signed-off-by: Lee Leahy <Leroy.P.Leahy@intel.com>
Reviewed-on: https://review.coreboot.org/18865
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>

src/arch/x86/mmap_boot.c

@@ -54,7 +54,7 @@ static int cbfs_master_header_props(struct cbfs_props *props)
 		return -1;
 
 	props->offset = header.offset;
-	if (CONFIG_ROM_SIZE != header.romsize)
+	if (header.romsize != CONFIG_ROM_SIZE)
 		props->size = CONFIG_ROM_SIZE;
 	else
 		props->size = header.romsize;