crypto: qat - expand CSR operations for QAT GEN4 devices

Extend the CSR operations for QAT GEN4 devices to allow saving and
restoring the rings state.

The new operations will be used as a building block for implementing the
state save and restore of Virtual Functions necessary for VM live
migration.

This adds the following operations:
 - read ring status register
 - read ring underflow/overflow status register
 - read ring nearly empty status register
 - read ring nearly full status register
 - read ring full status register
 - read ring complete status register
 - read ring exception status register
 - read/write ring exception interrupt mask register
 - read ring configuration register
 - read ring base register
 - read/write ring interrupt enable register
 - read ring interrupt flag register
 - read/write ring interrupt source select register
 - read ring coalesced interrupt enable register
 - read ring coalesced interrupt control register
 - read ring flag and coalesced interrupt enable register
 - read ring service arbiter enable register
 - get ring coalesced interrupt control enable mask

Signed-off-by: Siming Wan <siming.wan@intel.com>
Reviewed-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Signed-off-by: Xin Zeng <xin.zeng@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>