Check the return code of the function qat_hal_rd_rel_reg() and return it
to the caller.

This is to fix the following warning when compiling the driver with
clang scan-build:

    drivers/crypto/qat/qat_common/qat_hal.c:1436:2: warning: 6th function call argument is an uninitialized value
Signed-off-by: Jack Xu <jack.xu@intel.com>
Co-developed-by: Zhehui Xiang <zhehui.xiang@intel.com>
Signed-off-by: Zhehui Xiang <zhehui.xiang@intel.com>
Reviewed-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>