soc/amd/stoneyridge: start header file for iomap

Create a new header file, iomap.h, which serves as a single
place for providing the address space definitions. Remove
the amd_defs.h file that had a single define in it.

Change-Id: I1b1aaa8c5d60d670c272ac7131faeb6b3edc1968
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/22318
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
2 files changed