ASoC: wcd-spi: add system suspend and resume functionality

When any SPI transaction is in progress or the SPI clock request
is active, the system suspend needs to be blocked to make sure
the pending transaction completes. If not blocked, it could result
into device crash due to unclocked access. Also, if other components
request resume through WDSP_EVENT_RESUME, we need to make sure the
system resume happens if the driver is already in suspended state.

CRs-Fixed: 1111863
Change-Id: I48a357b93bd46caa30e22f82299b70393f497827
Signed-off-by: Bhalchandra Gajare <gajare@codeaurora.org>