drivers: gpio: Change DW driver to use depends on instead of select

In prepration for configuring I2C/SPI defaults at the board level,
change the DesignWare GPIO driver's clock gate option to depend on clock
control instead of selecting clock control. This breaks a Kconfig
dependency loop when adding the following to a board's
Kconfig.defconfig:

config SPI
	default y if SENSOR

There aren't any in-tree users that enable the clock gate option, so
there aren't any places in-tree that now need to enable the clock
control driver. Out-of-tree users that set CONFIG_GPIO_DW_CLOCK_GATE=y
will now also need to set CONFIG_CLOCK_CONTROL=y.

Signed-off-by: Maureen Helm <maureen.helm@intel.com>