Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/clk/mmp/clk-frac.c b/drivers/clk/mmp/clk-frac.c
index cb43d54..90bf181 100644
--- a/drivers/clk/mmp/clk-frac.c
+++ b/drivers/clk/mmp/clk-frac.c
@@ -78,11 +78,10 @@
 	struct mmp_clk_factor_masks *masks = factor->masks;
 	int i;
 	unsigned long val;
-	unsigned long prev_rate, rate = 0;
+	unsigned long rate = 0;
 	unsigned long flags = 0;
 
 	for (i = 0; i < factor->ftbl_cnt; i++) {
-		prev_rate = rate;
 		rate = (((prate / 10000) * factor->ftbl[i].den) /
 			(factor->ftbl[i].num * factor->masks->factor)) * 10000;
 		if (rate > drate)