arm64: dts: imx8-ss-conn: fix usb lpcg indices

usb2_lpcg: clock-controller@5b270000 {
	...                                                    Col1  Col2
	clocks = <&conn_ahb_clk>, <&conn_ipg_clk>;           // 0     6
	clock-indices = <IMX_LPCG_CLK_6>, <IMX_LPCG_CLK_7>;  // 0     7
        ...
};

Col1: index, which existing dts try to get.
Col2: actual index in lpcg driver.

usbotg1: usb@5b0d0000 {
	...
	clocks = <&usb2_lpcg 0>;
			     ^^
Should be:
	clocks = <&usb2_lpcg IMX_LPCG_CLK_6>;
};

usbphy1: usbphy@5b100000 {
	clocks = <&usb2_lpcg 1>;
			     ^^
SHould be:
	clocks = <&usb2_lpcg IMX_LPCG_CLK_7>;
};

Arg0 is divided by 4 in lpcg driver. So lpcg will do dummy enable. Fix it
by use correct clock indices.

Cc: stable@vger.kernel.org
Fixes: 8065fc93 ("arm64: dts: imx8dxl: add usb1 and usb2 support")
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>