wil6210: optimize index manipulation in wil_vring_reap_rx

Use temporal variable for often used vring->swhead;
and use proper index in debug printing - vring->swhead
used before was modified in wil_vring_advance_head
and then increased value was used in debug print

Change-Id: If8a2d289d7605dfc60fa30fbd6ab4c9b3724a425
Signed-off-by: Vladimir Kondratiev <qca_vkondrat@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Git-commit: 148416a973e0a07fa94a0de90dae92763b282311
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-testing.git


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