certs: remove noisy messages while generating the signing key

When you run Kbuild with the parallel option -j, the messages from this
rule and others are interleaved, like follows:

    ###
      CC      arch/x86/mm/pat/set_memory.o
    ### Now generating an X.509 key pair to be used for signing modules.
    ###
    ### If this takes a long time, you might wish to run rngd in the
    ### background to keep the supply of entropy topped up.  It
      CC      arch/x86/events/intel/bts.o
      HDRTEST usr/include/linux/qnx4_fs.h
      CC      arch/x86/events/zhaoxin/core.o
    ### needs to be run as root, and uses a hardware random
    ### number generator if one is available.
      AR      init/built-in.a
    ###

On modern machines, it does not take a long time to generate the key.

Remove the ugly log messages.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

certs/Makefile

@@ -80,23 +80,12 @@ endif
 endif # CONFIG_MODULE_SIG_KEY_TYPE_RSA
 
 $(obj)/signing_key.pem: $(obj)/x509.genkey
-	@$(kecho) "###"
-	@$(kecho) "### Now generating an X.509 key pair to be used for signing modules."
-	@$(kecho) "###"
-	@$(kecho) "### If this takes a long time, you might wish to run rngd in the"
-	@$(kecho) "### background to keep the supply of entropy topped up.  It"
-	@$(kecho) "### needs to be run as root, and uses a hardware random"
-	@$(kecho) "### number generator if one is available."
-	@$(kecho) "###"
 	$(Q)openssl req -new -nodes -utf8 -$(CONFIG_MODULE_SIG_HASH) -days 36500 \
 		-batch -x509 -config $(obj)/x509.genkey \
 		-outform PEM -out $(obj)/signing_key.pem \
 		-keyout $(obj)/signing_key.pem \
 		$(keytype_openssl) \
 		$($(quiet)redirect_openssl)
-	@$(kecho) "###"
-	@$(kecho) "### Key pair generated."
-	@$(kecho) "###"
 
 quiet_cmd_copy_x509_config = COPY    $@
       cmd_copy_x509_config = cat $(srctree)/$(src)/default_x509.genkey > $@