The `call int-multiply` couldn't handle the Kconfig option being a
string so do the calculation in bash.
Tested on:
* Qemu
* StarLite Mk III
Signed-off-by: Sean Rhodes <sean@starlabs.systems>
Change-Id: I1879d7efd504e2c42dadb12d2d8add4f69ca7b9c
Reviewed-on: https://review.coreboot.org/c/coreboot/+/66161
Reviewed-by: Matt DeVillier <matt.devillier@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Lean Sheng Tan <sheng.tan@9elements.com>
6388a5b892