msm: ipa: optimize sys2bam data path

add the ability to provide DMA address of an skb sent
to IPA driver if it was already DMA mapped for saving the
MIPS of mapping the same buffer again.

Change-Id: Iaf06e45d0d4fab0a5968688eae768b79148e8270
Acked-by: Ady Abraham <adya@qti.qualcomm.com>
Signed-off-by: Gidon Studinski <gidons@codeaurora.org>