lib/gcov-glue.c: Remove trailing number from COVERAGE_MAGIC macro

The COVERAGE_MAGIC macro has a trailing `4' on it, which makes it a
64-bit large integer, as opposed to a 32-bit unsigned integer, as
originally designated in `util/cbmem/cbmem.c'. Remove this number so
building with CODE_COVERAGE will succeed.

Change-Id: Ib5d7f2704a4c092c3eca6f62e219edb30950d793
Signed-off-by: Jean Lucas <jean@4ray.co>
Reviewed-on: https://review.coreboot.org/13520
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Martin Roth <martinroth@google.com>

src/lib/gcov-glue.c

@@ -34,7 +34,7 @@ typedef struct file {
 
 #define COVERAGE_SIZE (32*1024)
 
-#define COVERAGE_MAGIC 0x584d41534
+#define COVERAGE_MAGIC 0x584d4153
 
 static FILE *current_file = NULL;
 static FILE *previous_file = NULL;