imx: mx6ull: Add AIPS3 initialization

Since the mx6ull adds the AIPS3, so enable its initialization.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Ye Li <ye.li@nxp.com>
Cc: Stefano Babic <sbabic@denx.de>