cfi_flash: Use __func__ macro instead of function name

printf/debug statements should not include the file name as a hardcoded
string, but instead use the __func__ macro. Fix all instances where this
occurs.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>

drivers/mtd/cfi_flash.c

@@ -555,7 +555,7 @@ static int flash_is_busy(flash_info_t *info, flash_sect_t sect)
 	default:
 		retval = 0;
 	}
-	debug("flash_is_busy: %d\n", retval);
+	debug("%s: %d\n", __func__, retval);
 	return retval;
 }