NFC: netlink: Add new netlink command NFC_CMD_ACTIVATE_TARGET

Some tag might get deactivated after some read or write tentative.
This may happen for example with Mifare Ultralight C tag when trying
to read the last 4 blocks (starting block 0x2c) configured as write
only.
NFC_CMD_ACTIVATE_TARGET will try to reselect the tag in order to
detect if it got remove from the field or if it is still present.

Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>