net: ipc_router: Use kernel internal uid and gid

Kernel UID and GID types are converted from integer to a structure
containing a value. Currently this conversion is protected using
UIDGID_STRICT_TYPE_CHECKS kernel config item.

Start using kernel uid and gid types to avoid any potential compilation
issues.

Change-Id: Ic52c4a75fc7250ece2908add8a7fa88ec253d78a
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>