wil6210: add handling of RX HTRSH interrupt

RX_HTRSH interrupt is handled in exactly the same manner
as RX_DONE interrupt - fetching accumulated packets from RX
ring. In addition there's a rate limitted warning message.

Change-Id: I9ff96f5badd3bc7e8656b7a30d2ef764c85bcffb
Signed-off-by: Vladimir Kondratiev <qca_vkondrat@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Git-commit: 40e391b4336aa79d0d7a65b924b7b4a334bd9e9b
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-testing.git


[hkadmany@codeaurora.org: trivial backport to kernel 3.10]
Signed-off-by: Hamad Kadmany <hkadmany@codeaurora.org>