NFC: Add dummy nfc_llc_shdlc_register definition

This is used when CONFIG_NFC_SHDLC is disabled.

Reported-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>