Earlier firmware was stored to a memory area allocated with kmalloc()
but finding a a contiguous area of memory long enough for the firmware is
very difficult in certain cases. better to allocate the memory for firmware
with vmalloc() instead and use a small buffer for DMA transfers.

Thanks to Eero Tamminen for the idea.
Signed-off-by: NKalle Valo <kalle.valo@nokia.com>
Reviewed-by: NVidhya Govindan <vidhya.govindan@nokia.com>
Signed-off-by: NLuciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>