mwifiex: add support for SD8801

SD8801 is Marvell's 1x1 802.11bgn offering.
This patch adds Device IDs for SD8801 and also defines card
structure which has definition for register offsets, buffer sizes etc.

Signed-off-by: Yogesh Ashok Powar <yogeshp@marvell.com>
Signed-off-by: Avinash Patil <patila@marvell.com>
Signed-off-by: Nishant Sarmukadam <nishants@marvell.com>
Signed-off-by: Cathy Luo <cluo@marvell.com>
Signed-off-by: Frank Huang <frankh@marvell.com>
Reviewed-by: James Cameron <quozl@laptop.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>