crypto: qat - rework the VF2PF interrupt handling logic

Change the VF2PF interrupt handler in the PF ISR and the definition of
the internal PFVF API to correct the current implementation, which can
result in missed interrupts.

More specifically, current HW generations consider a write to the mask
register, regardless of the value, as an acknowledge of any pending
VF2PF interrupt. Therefore, if there is an interrupt between the source
register read and the mask register write, such interrupt will not be
delivered and silently acknowledged, resulting in a lost VF2PF message.

To work around the problem, rather than disabling specific interrupts,
disable all the interrupts and re-enable only the ones that we are not
serving (excluding the already disabled ones too). This will force any
other pending interrupt to be triggered and be serviced by a subsequent
ISR.

This new approach requires, however, changes to the interrupt related
pfvf_ops functions. In particular, get_vf2pf_sources() has now been
removed in favor of disable_pending_vf2pf_interrupts(), which not only
retrieves and returns the pending (and enabled) sources, but also
disables them.
As a consequence, introduce the adf_disable_pending_vf2pf_interrupts()
utility in place of adf_disable_vf2pf_interrupts_irq(), which is no
longer needed.

Cc: stable@vger.kernel.org
Fixes: 993161d3 ("crypto: qat - fix handling of VF to PF interrupts")
Signed-off-by: Marco Chiappero <marco.chiappero@intel.com>
Co-developed-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Signed-off-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>