FROMGIT: net: ipa: don't disable interrupt on suspend

No completion interrupts will occur while an endpoint is suspended,
nor when a channel has been stopped for suspend.  So there's no need
to disable the interrupt during suspend and re-enable it when
resuming.  Without any interrupts occurring, there is no need to
disable/re-enable NAPI for channel suspend/resume either.

We'll only enable NAPI and the interrupt when we first start the
channel, and disable it again only when it's "really" stopped.

To accomplish this, move the enable/disable calls out of
__gsi_channel_start() and __gsi_channel_stop(), and into
gsi_channel_start() and gsi_channel_stop() instead.

Add a call to napi_synchronize() to gsi_channel_suspend(), to ensure
NAPI polling is done before moving on.

Signed-off-by: Alex Elder <elder@linaro.org>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
(cherry picked from commit a65c0288
 https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git

 master)

BUG=b:177097776
TEST=Modem functional, No IPA hang in suspend stress test

Signed-off-by: Sujit Kautkar <sujitka@chromium.org>
Change-Id: I51073954c33eae76d6724a7fc089c64f84ba88c4
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/2674469


Reviewed-by: Sean Paul <seanpaul@chromium.org>
Reviewed-by: Evan Green <evgreen@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/2685032