msm: ipa3: Send actual DL flt rule to Q6

Currently max length size of DL flt rule is
sent to Q6. But 64K memory allocation is not
always guaranteed. Send actual size of DL flt rule
to Q6 to avoid memory error and install flt rule.

Change-Id: Id5f7bbb616c23feb6efbacd288f790432156630b
Signed-off-by: Pooja Kumari <kumarip@codeaurora.org>