b43: Add RX side DMA memory barrier
b43: Add RX side DMA memory barrier

This adds a memory barrier to ensure the writes to the ring memory
are committed before the DMA ring pointer is updated.
We do a similar thing on the TX side already.

Signed-off-by: Michael Buesch <6b0d31c0d563223024da45691584643ac78c96e8@bues.ch>
Signed-off-by: John W. Linville <2a53bac7a5d324865ef46ec4c38b2c0fba1456b4@tuxdriver.com>

TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs