Makefile.mk: Fix int-shift-left

commit 4a8d73d6a4 ("Makefile.mk: Remove bc dependency") broke the left
shift, since the expr tool does not support shifting operations.

This patch uses the left shift operator inside arithmetic expansion.
Every posix shell should support this.

Tested:
Build amd/birman mainboard and check that the soft-fuse parameter
doesn't change.

Signed-off-by: Maximilian Brune <maximilian.brune@9elements.com>
Change-Id: If3b29dae727875b0788100a2cb02c86736ffaf8c
Reviewed-on: https://review.coreboot.org/c/coreboot/+/83377
Reviewed-by: Felix Singer <service+coreboot-gerrit@felixsinger.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Martin L Roth <gaumless@gmail.com>
Reviewed-by: Matt DeVillier <matt.devillier@gmail.com>

0 files changed, 0 insertions, 0 deletions