x86: Adjust mrccache_get_region() to support get_mmap()

It is now possible to obtain the memory map for a SPI controllers instead
of having it hard-coded in the device tree. Update the code to support
this.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
1 file changed