Add xhcbios and ahcibios rom handling

Add xhcbios and ahcibios rom handling

This change adds xhci and ahci bios rom handling that
is similar to the vgabios rom handling in the arch/x86
Makefile.inc to the Persimmon and Torpedo mainboards.
It also adds the basis for AHCI BIOS rom handling to
the Persimmon Kconfig.

Change-Id: I527a906323ae483cfa2ca0785f3adb43e88fd84b
Signed-off-by: Frank Vibrans <frank.vibrans@amd.com>
Signed-off-by: efdesign98 <efdesign98@gmail.com>
Reviewed-on: http://review.coreboot.org/109
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marcj303@gmail.com>