ntb: intel: fix port config status offset for SPR

The field offset for port configuration status on SPR has been changed to
bit 14 from ICX where it resides at bit 12. By chance link status detection
continued to work on SPR. This is due to bit 12 being a configuration bit
which is in sync with the status bit. Fix this by checking for a SPR device
and checking correct status bit.

Fixes: 26bfe3d0 ("ntb: intel: Add Icelake (gen4) support for Intel NTB")
Tested-by: Jerry Dai <jerry.dai@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>