NFC: nxp-nci: constify nxp_nci_phy_ops structure

The only instance of a nxp_nci_phy_ops structure is never modified.  Thus
the declaration of the structure and all references to the structure type
can be made const.

Done with the help of Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>