qcacmn: Add cfg_dp_sg_enable to get ini key dp_sg_support

Add cfg_dp_sg_enable to get ini key dp_sg_support by cdp_cfg_get.
And add some comments for CFG_DP_SG to clarify more.

Change-Id: I34de242eacbdcf55398afe64b91f5534f205fa22
CRs-Fixed: 2822536
4 files changed