mwifiex: add support for 8997 chipset

This patch adds support for 8997 chipset to mwifiex
with SDIO/PCIe/USB interface.

The corresponding firmware image files are located in:
"mrvl/sd8997_uapsta.bin"
"mrvl/pcie8997_uapsta.bin"
"mrvl/usb8997_uapsta.bin"

Signed-off-by: Zhaoyang Liu <liuzy@marvell.com>
Signed-off-by: Cathy Luo <cluo@marvell.com>
Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>