Correct vpo_sd_1v8_3v3 regulator max voltage to 3.3V

Fixes: 9868bc585ae2 ("ARM: dts: Add support for dra718-evm")
Signed-off-by: Ravikumar Kattekola <rk@ti.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>