wil6210: add NIC memory region mac_rgf_ext

Firmware defines new memory region, mac_rgf_ext
that need to be accessed from the host for debug purposes.

Add corresponded mapping

Change-Id: If3b602228a5c8da512635f2f255d8466d0d81cfc
Signed-off-by: Vladimir Kondratiev <qca_vkondrat@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
Git-commit: 0fd37ff8ee3844032b2d6dc8a8cc73ce41d2ce0b
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-testing.git


Signed-off-by: Hamad Kadmany <hkadmany@codeaurora.org>