Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/tools/objtool/Build b/tools/objtool/Build
index 749becd..8dc4f08 100644
--- a/tools/objtool/Build
+++ b/tools/objtool/Build
@@ -9,6 +9,7 @@
 objtool-y += objtool.o
 
 objtool-y += libstring.o
+objtool-y += libctype.o
 objtool-y += str_error_r.o
 
 CFLAGS += -I$(srctree)/tools/lib
@@ -17,6 +18,10 @@
 	$(call rule_mkdir)
 	$(call if_changed_dep,cc_o_c)
 
+$(OUTPUT)libctype.o: ../lib/ctype.c FORCE
+	$(call rule_mkdir)
+	$(call if_changed_dep,cc_o_c)
+
 $(OUTPUT)str_error_r.o: ../lib/str_error_r.c FORCE
 	$(call rule_mkdir)
 	$(call if_changed_dep,cc_o_c)