gen9_avc_encoder: macro optimization
gen9_avc_encoder: macro optimization

Avoid duplicated multiplication, do the frame size
calculation once and reuse the result.

Signed-off-by: Sreerenj Balachandran <8526e100bdc7a12d85af109c9f42b86756e50e67@intel.com>
(cherry picked from commit 38a124e1f94682162ac12c00f8106ac6a627b3cd)

01org/iotg-lin-gfx-va-driver,01org/iotg-lin-gfx-va-driver,01org/iotg-lin-gfx-va-driver,01org/iotg-lin-gfx-va-driver,01org/iotg-lin-gfx-va-driver