msm: ipa: change default WLAN HOLB timer duration

This change is needed to see good bi-directional WLAN
throughputs with both TX and RX paths using IPA. This
change also adds support to allow changing the HOLB
(head-of-line-blocking) configuration (enable/ disable
and timer duration) dynamically for WLAN TX pipes.

Change-Id: I0d80b345ee3daa948a2616bf8221ffae9c294f1a
Signed-off-by: Ravi Gummadidala <rgummadi@codeaurora.org>