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/timer.c

@@ -20,7 +20,7 @@
 
 __attribute__((weak)) void init_timer() { /* do nothing */ }
 
-void udelay(unsigned usec)
+void udelay(unsigned int usec)
 {
 	struct stopwatch sw;