src/lib: Add "int" following "unsigned"

Fix the following warning detected by checkpatch.pl:

WARNING: Prefer 'unsigned int' to bare use of 'unsigned'

The remaining 37 warnings in gcov-io.c and libgcov.c are all false
positives generated by checkpatch detecting a symbol or function name
ending in _unsigned.

TEST=Build and run on Galileo Gen2

Change-Id: I9f1b71993caca8b3eb3f643525534a937d365ab3
Signed-off-by: Lee Leahy <Leroy.P.Leahy@intel.com>
Reviewed-on: https://review.coreboot.org/18695
Tested-by: build bot (Jenkins)
Reviewed-by: Philippe Mathieu-Daudé <philippe.mathieu.daude@gmail.com>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>

src/lib/b64_decode.c

@@ -84,10 +84,10 @@ size_t b64_decode(const uint8_t *input_data,
 		  uint8_t *output_data)
 {
 	struct buffer_descriptor bd;
-	unsigned interim = 0;
+	unsigned int interim = 0;
 	size_t output_size = 0;
 	/* count of processed input bits, modulo log2(64) */
-	unsigned bit_count = 0;
+	unsigned int bit_count = 0;
 
 	/*
 	 * Keep the context on the stack to make things easier if this needs