msm: vidc: Fix scaling capability for encoders

Scaling capability are defined in Q16 format. Existing
capability indicates that the capability is 16 times i.e
output dimension can be scaled to 1/16th of input dimension.
As per specification, the achievable ratio is 8.

Change-Id: Ib9e005a055e604d3173dd8cd376d3b6666f2c12c
Signed-off-by: Vikash Garodia <vgarodia@codeaurora.org>