msm: ipa: Fix to use GFP_DMA flag

IPAv2 hardware works with 32 bit addressing,
so allocate a kernel memory using GFP_DMA flag
which is processed by IPA hardware. Added code
changes to free correct tx_pkt pointer in fail_dma_map condition.

Change-Id: I5f7005c3bf89275fd56af648ee5bf1b3d06afc38
Acked-by: Ashok Vuyyuru <avuyyuru@qti.qualcomm.com>
Acked-by: Mohammed Javid <mjavid@qti.qualcomm.com>
Signed-off-by: Utkarsh Saxena <usaxena@codeaurora.org>