pinctrl: aspeed-g5: Fix pin association of SPI1 function

The SPI1 function was associated with the wrong pins: The functions that
those pins provide is either an SPI debug or passthrough function
coupled to SPI1. Make the SPI1 mux function configure the relevant pins
and associate new SPI1DEBUG and SPI1PASSTHRU functions with the pins
that were already defined.

The notation used in the datasheet's multi-function pin table for the SoC is
often creative: in this case the SYS* signals are enabled by a single bit,
which is nothing unusual on its own, but in this case the bit was also
participating in a multi-bit bitfield and therefore represented multiple
functions. This fact was overlooked in the original patch.

Fixes: 56e57cb6 (pinctrl: Add pinctrl-aspeed-g5 driver)
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>