msm: ipa: memory optimization

Previously, size of skb requested on receive path was 2048 bytes.
With built-in headroom and skb shared info, final requested size
exceeded 2048 bytes requiring 2 pages (with page size of 2K). This
can lead to OOM during CAT4 E2E ECM DL fragmented scenario. Reduce
requested size to cause final allocation to fit in 1 page. This
reduction does not impact functionality due to standard MTU of
1500 bytes.

Change-Id: I3cd8dd6fb86b0097ad6de1bb18282447e4024766
Signed-off-by: Ravi Gummadidala <rgummadi@codeaurora.org>