[rom_ctrl] Remove bogus target from Makefile

This came from a copy-paste from an OTBN Makefile: there has never
been an asm_check target here.

Signed-off-by: Rupert Swarbrick <rswarbrick@lowrisc.org>

hw/ip/rom_ctrl/util/Makefile

diff --git a/hw/ip/rom_ctrl/util/Makefile b/hw/ip/rom_ctrl/util/Makefile
index 99116fd..5341158 100644
--- a/hw/ip/rom_ctrl/util/Makefile
+++ b/hw/ip/rom_ctrl/util/Makefile
@@ -3,7 +3,7 @@
 # SPDX-License-Identifier: Apache-2.0
 
 .PHONY: all
-all: lint asm-check
+all: lint
 
 # We need a directory to build stuff and use the "rom_ctrl/util" namespace
 # in the top-level build-out directory.