kbuild: remove redundant target cleaning on failure

Since commit 9c2af1c737 ("kbuild: add .DELETE_ON_ERROR special
target"), the target file is automatically deleted on failure.

The boilerplate code

  ... || { rm -f $@; false; }

is unneeded.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

certs/Makefile

@@ -22,7 +22,7 @@ $(obj)/system_certificates.o: $(obj)/x509_certificate_list
 AFLAGS_system_certificates.o := -I$(srctree)
 
 quiet_cmd_extract_certs  = EXTRACT_CERTS   $(patsubst "%",%,$(2))
-      cmd_extract_certs  = scripts/extract-cert $(2) $@ || ( rm $@; exit 1)
+      cmd_extract_certs  = scripts/extract-cert $(2) $@
 
 targets += x509_certificate_list
 $(obj)/x509_certificate_list: scripts/extract-cert $(SYSTEM_TRUSTED_KEYS_SRCPREFIX)$(SYSTEM_TRUSTED_KEYS_FILENAME) FORCE