NFC: Fix empty HCI message list check

list_first_entry() will never return NULL. Instead use
list_for_each_entry_safe() to iterate through the list.

Signed-off-by: Mathias Jeppsson <mathias.jeppsson@sonymobile.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>