src/include: Indent code using tabs

Fix the following error and warning detected by checkpatch.pl:

ERROR: code indent should use tabs where possible
WARNING: please, no spaces at the start of a line

TEST=Build and run on Galileo Gen2

Change-Id: I487771b8f4d7e104457116b772cd32df5cd721a6
Signed-off-by: Lee Leahy <Leroy.P.Leahy@intel.com>
Reviewed-on: https://review.coreboot.org/18646
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>

src/include/cpu/amd/sc520.h

@@ -151,7 +151,7 @@ struct gptimers {
 struct watchdog {
 	unsigned short ctl;
 	unsigned short cntll;
-        unsigned short cntlh;
+	unsigned short cntlh;
 	unsigned char pad[10];
 };