We duplicate the 'depends on' in almost every Kconfig here, and it's
getting out of hand now that we have tens of options for various SoC
drivers here. Let's clean it up a little by making a menuconfig for a
submenu and adding an if wrapper around the driver section.

Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Taniya Das <tdas@codeaurora.org>
Signed-off-by: NStephen Boyd <sboyd@kernel.org>