MLK-16564-02 dts: imx7ulp-evk: add rpmsg gpio PTA and PTB support

MLK-16564-02 dts: imx7ulp-evk: add rpmsg gpio PTA and PTB support

Add rpmsg gpio PTA and PTB support.
Since currently M4 image support dynamical channel allocation,
and reserve below memory for kernel service and app channel:
        * --0x9FF00000~0x9FF0FFFF: pmic,pm,audio,keys,gpio
        * --0x9FF10000~0x9FF1FFFF: pingpong,virtual tty

Change the rpmsg instances of  A core part to sync with M core.

Test M4 image built from Wayne Feng, M4 image commit ID: b1321d4aca82

Reviewed-by: Richard Zhu <hongxing.zhu@nxp.com>
Reviewed-by: Robin Gong <yibin.gong@nxp.com>
Signed-off-by: Fugang Duan <fugang.duan@nxp.com>