NFC: digital: Fix sens_res endiannes handling

This was triggered by the following sparse warning:

net/nfc/digital_technology.c:272:20: sparse: cast to restricted __be16

The SENS_RES response must be treated as __le16 with the first byte
received as LSB and the second one as MSB. This is the way neard
handles it in the sens_res field of the nfc_target structure which is
treated as u16 in cpu endianness. So le16_to_cpu() is used on the
received SENS_RES instead of memcpy'ing it.

SENS_RES test macros have also been fixed accordingly.

Signed-off-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>