Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/kernel/printk/braille.c b/kernel/printk/braille.c
index 1d21eba..17a9591 100644
--- a/kernel/printk/braille.c
+++ b/kernel/printk/braille.c
@@ -11,11 +11,18 @@
 
 int _braille_console_setup(char **str, char **brl_options)
 {
-	if (!strncmp(*str, "brl,", 4)) {
+	size_t len;
+
+	len = str_has_prefix(*str, "brl,");
+	if (len) {
 		*brl_options = "";
-		*str += 4;
-	} else if (!strncmp(*str, "brl=", 4)) {
-		*brl_options = *str + 4;
+		*str += len;
+		return 0;
+	}
+
+	len = str_has_prefix(*str, "brl=");
+	if (len) {
+		*brl_options = *str + len;
 		*str = strchr(*brl_options, ',');
 		if (!*str) {
 			pr_err("need port name after brl=\n");