Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/x86/math-emu/fpu_trig.c b/arch/x86/math-emu/fpu_trig.c
index 783c509..127ea54 100644
--- a/arch/x86/math-emu/fpu_trig.c
+++ b/arch/x86/math-emu/fpu_trig.c
@@ -1352,7 +1352,7 @@
 		case TW_Denormal:
 			if (denormal_operand() < 0)
 				return;
-
+			/* fall through */
 		case TAG_Zero:
 		case TAG_Valid:
 			setsign(st0_ptr, getsign(st0_ptr) ^ getsign(st1_ptr));