MdeModulePkg/AtaAtapiPassThru: cache EnabledPciAttributes

MdeModulePkg/AtaAtapiPassThru: cache EnabledPciAttributes

Both AtaAtapiPassThruStart() and AtaAtapiPassThruStop() fetch the
supported attributes of the device, just so they can toggle the
IO+MMIO+BusMaster subset.

After we compute this bitmask in AtaAtapiPassThruStart(), we can cache it
for later, and save the fetch in AtaAtapiPassThruStop().

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>