ARM: dts: koelsch: enable UHS for SDHI 0, 1 & 3

Add the "1v8" pinctrl state and sd-uhs-sdr50 property to SDHI{0,1,2}.

Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Acked-by: Wolfram Sang <wsa+renesas@sang-engineering.com>