src/lib: Remove braces for single statements

Fix the following warning detected by checkpatch.pl:

WARNING: braces {} are not necessary for single statement blocks

TEST=Build and run on Galileo Gen2

Change-Id: Ie4b41f6fb75142ddd75103a55e0347ed85e7e873
Signed-off-by: Lee Leahy <Leroy.P.Leahy@intel.com>
Reviewed-on: https://review.coreboot.org/18697
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Tested-by: build bot (Jenkins)

src/lib/halt.c

@@ -18,7 +18,6 @@
 #include <halt.h>
 
 void halt(void) {
-	while (1) {
+	while (1)
 		hlt();
-	}
 }