Current code assumes that all the irqs registers offsets can be
accessed in all the hw revisions; this is not the case for some
targets that should not access some of the irq registers.
This change adds the support to selectively remove the irqs that
are not supported in some of the hw revisions.

Changes in v1:
 - Add support to selectively remove the hw irqs that are not
   not supported.

Changes in v2:
 - Remove unrelated changes.

Changes in v3:
 - Remove change-id (Stephen Boyd).
 - Add colon in variable description to match kernel-doc (Stephen Boyd).
 - Change macro-y way of variable description (Jordon Crouse).
 - Remove unnecessary if checks (Jordon Crouse).
 - Remove extra blank line (Jordon Crouse).

Changes in v4:
 - Remove checkpatch errors.
Signed-off-by: Shubhashree Dhar <dhar@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>