IB/hfi1: Check upper-case EFI variables

The EFI variable that provides board ID is named
by the PCI address of the device, which is published
in upper-case, while the HFI1 driver reads the EFI
variable in lower-case.
This prevents returning the correct board id when
queried through sysfs. Read EFI variables in
upper-case if the lower-case read fails.

Reviewed-by: Easwar Hariharan <easwar.hariharan@intel.com>
Signed-off-by: Sebastian Sanchez <sebastian.sanchez@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>