usb: gadget: Add support to RNDIS PacketAlignmentFactor setting

Add support for RNDIS to set PacketAlignmentFactor from the rndis
function driver.
For QC RNDIS function driver the alignment was set to 4 bytes due to
restrictions from the A2.

CRs-Fixed: 394587
Change-Id: I74296649a24597a31f1303f590239baf9ec9164d
Signed-off-by: Ofir Cohen <ofirc@codeaurora.org>