FM: fix the bug where SMD interrupts might not be processed

radio_hci_smd_recv_event() function allocates memory with
GFP_KERNEL which might sleep which can cause the interrupts
not to be processed. This patch changes GFP_KERNEL to
GFP_ATOMIC which prevents the function from sleeping
while allocating memory.

Change-Id: I0ff0feabf972c4ff5a9fb8474ec68611a13668bf
Signed-off-by: Ankur Nandwani <ankurn@codeaurora.org>