ARM: dts: imx7: Move PCIe out of AIPS3

The AIPS3 on iMX7 is at 0x30800000 and is 0x400000 long, the PCIe IP
is not part of this AIPS range. Move it to /soc node.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: Peng Fan <peng.fan@nxp.com>
Cc: Richard Zhu <hongxing.zhu@nxp.com>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: linux-imx@nxp.com
Signed-off-by: Shawn Guo <shawnguo@kernel.org>