pinctrl: sh-pfc: r8a77990: Fix MOD_SEL1 bit30 when using SSI_SCK2 and SSI_WS2

According to the R-Car Gen3 Hardware Manual Errata for Rev 1.00 of Aug
24, 2018, there is no need to configure MOD_SEL1 bit30 when the
SSI_SCK2_{A,B} or SSI_WS2_{A,B} pin functions are selected.

Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
[geert: Remove now unused definitions, mark MOD_SEL1 bit30 reserved]
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>