ARM: dts: aspeed-g6: add FWQSPI group in pinctrl dtsi

ARM: dts: aspeed-g6: add FWQSPI group in pinctrl dtsi

Add FWSPIDQ2 and FWSPIDQ3 group to support AST2600 FW SPI quad mode.
These pins can be used with dedicated FW SPI pins - FWSPICS0#,
FWSPICK, FWSPIMOSI and FWSPIMISO.

Signed-off-by: Johnny Huang <johnny_huang@aspeedtech.com>
Signed-off-by: Jae Hyun Yoo <quic_jaehyoo@quicinc.com>
Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Link: https://lore.kernel.org/r/20220329173932.2588289-7-quic_jaehyoo@quicinc.com
Signed-off-by: Joel Stanley <joel@jms.id.au>