Add missing noreturn attribute to various functions

Signed-off-by: Thomas Wood <thomas.wood@intel.com>

tools/intel_display_poller.c

@@ -946,7 +946,7 @@ static const char *test_name(enum test test, int pipe, int bit, bool test_pixel_
 	}
 }
 
-static void usage(const char *name)
+static void __attribute__((noreturn)) usage(const char *name)
 {
 	fprintf(stderr, "Usage: %s [options]\n"
 		" -t,--test <pipestat|iir|framecount|flipcount|pan|flip|surflive|wrap|field>\n"

tools/intel_gpu_frequency.c

@@ -142,7 +142,7 @@ static int get_frequency(struct freq_info *freq_info)
 	return val;
 }
 
-static void
+static void __attribute__((noreturn))
 usage(const char *prog)
 {
 	printf("%s A program to manipulate Intel GPU frequencies.\n\n", prog);