sata_mv: don't read hc_irq_cause
sata_mv: don't read hc_irq_cause

Remove silly read-modify-write sequences when clearing interrupts
in hc_irq_cause.  This gets rid of unneeded MMIO reads, resulting in
a slight performance boost when switching between EDMA and non-EDMA
modes (eg. for cache flushes).

Signed-off-by: Mark Lord <a3587211cfc5fa09c6928d027426e9cd2c992c79@pobox.com>
Signed-off-by: Jeff Garzik <15f615bf7d20c2937c7eb5aa759110fd6768848c@redhat.com>

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