log: change line counter to unsigned

The incremental counter of logged lines is a signed int.

Change it to unsigned, since negative values has no sense in this
context.

Change-Id: Ia75f9ca038bba385c5f88fb9fa368faaf055f9a3
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/9401
Reviewed-by: R. Diez <rdiez-2006@rd10.de>
Tested-by: jenkins

src/helper/log.c

@@ -47,7 +47,7 @@ static const char * const log_strings[7] = {
 	"Debug: ",  /* corresponds to LOG_LVL_DEBUG_USB */
 };
 
-static int count;
+static unsigned int count;
 
 /* forward the log to the listeners */
 static void log_forward(const char *file, unsigned int line, const char *function, const char *string)
@@ -110,7 +110,7 @@ static void log_puts(enum log_levels level,
 #error "Configuration error: Neither mallinfo() nor mallinfo2() are available."
 #endif
 #endif
-		fprintf(log_output, "%s%d %" PRId64 " %s:%d %s()"
+		fprintf(log_output, "%s%u %" PRId64 " %s:%d %s()"
 #ifdef _DEBUG_FREE_SPACE_
 #ifdef HAVE_MALLINFO2
 			" %zu"