The check should be for setup function pointer.

This patch fixes NULL pointer dereference issue for NCI
based NFC driver which doesn't define setup handler.
Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>