NFC: nfcmrvl: double free on error path

The nci_spi_send() function calls kfree_skb(skb) on both error and
success so this extra kfree_skb() is a double free.

Fixes: caf6e49b ("NFC: nfcmrvl: add spi driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>