src: Substitute __FUNCTION__ with __func__

The former is not standard C, and we primarily use the latter form.

Change-Id: Ia7091b494ff72588fb6910710fd72165693c1ac5
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/42516
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by:  Felix Singer <felixsinger@posteo.net>
Reviewed-by: Christian Walter <christian.walter@9elements.com>

src/drivers/pc80/tpm/tis.c

@@ -395,7 +395,7 @@ static u32 tis_probe(void)
 
 	didvid = tpm_read_did_vid(0);
 	if (!didvid || (didvid == 0xffffffff)) {
-		printf("%s: No TPM device found\n", __FUNCTION__);
+		printf("%s: No TPM device found\n", __func__);
 		return TPM_DRIVER_ERR;
 	}