NFC: digital: Add digital framing calls when in target mode

Add new "NFC_DIGITAL_FRAMING_*" calls to the digital
layer so the driver can make the necessary adjustments
when performing anticollision while in target mode.

The driver must ensure that the effect of these calls
happens after the following response has been sent but
before reception of the next request begins.

Acked-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>