msm: ipa: change holb timer value for A2 consumer end-points

Change duration from 0x7f to 0xff. This change is needed for
good bi-directional throughputs.

Change-Id: I769e5734f77f54cbc1b8794075ab9e44c3b80d30
Signed-off-by: Ravi Gummadidala <rgummadi@codeaurora.org>