ARM: dts: r8a7790: fix max-frequency for SDHI

The wrong values come from an old datasheet (H2 v0.6). Anything later
has the fixed value of 195MHz (H2 v0.7 up to Gen2-common V2.0).

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>