cnss: Support custom WLAN SDIO VDD-XTAL voltage

VDD-XTAL for WLAN SDIO requires a minimum required voltage
of 1.62V and a maximum voltage of 3.465V. With current CNSS
driver, a typical fixed voltage of 1.8V is supplied to
VDD-XTAL. On platforms where 1.8V is not possible but a minimum
voltage is possible, VDD-XTAL will not be able to be supplied.

Thus add CNSS SDIO dts options to set custom minimum and maximum
voltage for VDD-XTAL.

Change-Id: Ibb7808b2f3a901c26fe87b3e9ecb73e7593223c1
Signed-off-by: jiad <jiad@codeaurora.org>