NFC: nci: hci: Fix releasing uninitialized skbs

Several of these goto exit; uses should be direct returns
as skb is not yet initialized by nci_hci_get_param().

Miscellanea:

o Use !memcmp instead of memcmp() == 0
o Remove unnecessary goto from if () {... goto exit;} else {...} exit:

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>