soc/intel/cmn/xhci: Add function to reset the XHCI controller

This patch adds `xhci_host_reset()` to reset XHCI controller and the
scope of this function is with SMM hence, compiling xhci.c for SMM as
well.

Also, refactored `xhci.c` code to keep PCI enumeration within the scope
of `ramstage` alone hence, guarded with `ENV_RAMSTAGE` env_variable.

BUG=b:227289581
TEST=Able to perform a call from `xhci_host_reset` from S5 smi handler.

Signed-off-by: Subrata Banik <subratabanik@google.com>
Change-Id: Ie0dc0a64044f291893931726d26c08c8b964a3cc
Reviewed-on: https://review.coreboot.org/c/coreboot/+/63551
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

0 files changed, 0 insertions, 0 deletions