net: msm_rmnet: extend SET_INGRESS_DATA_FORMAT to include AGG data

Introduced new format flag for RMNET_IOCTL_SET_INGRESS_DATA_FORMAT:
RMNET_IOCTL_INGRESS_FORMAT_AGG_DATA
This flag is set by the entity callint the IOCTL if the
ingress_format union has been populated with a valid aggregation count
and buffer size.

Change-Id: Icb30c99e69062736c343591226fbdb499aa47a41
Signed-off-by: Harout Hedeshian <harouth@codeaurora.org>