rom.sh: check grub dry build in mkhelper

Signed-off-by: Leah Rowe <leah@libreboot.org>

config/data/grub/mkhelper.cfg

@@ -4,4 +4,4 @@ bootstrapargs="--gnulib-srcdir=gnulib/ --no-git"
 configureargs="--with-platform=coreboot --disable-werror"
 makeargs="FS_PAYLOAD_MODULES=\"\""
 buildtype="autohell"
-mkhelper="mkpayload_grub"
+mkhelper="$if_not_dry_build mkpayload_grub"

include/fw/rom.sh

@@ -40,9 +40,6 @@ mkpayload_grub()
 {
 	eval "`newvar grub_modules grub_install_modules`"
 
-	$if_dry_build \
-		return 0
-
 	. "$grubdata/module/$tree" || \
 	    err "Can't read '$grubdata/module/$tree'" "mkpayload_grub" "$@"