pinctrl: sh-pfc: rcar-gen3: Rename RTS{0,1,3,4}# pin function definitions

According to the R-Car Gen3 Hardware Manual Errata for Rev 1.50 of
Feb 12, 2019, the RTS{0,1,3,4}_#/TANS pin names defined in the GPSR and
IPSR registers are renamed to RTS{0,1,3,4}_#.
This patch updates the pin control drivers to reflect this.

Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
[geert: Update R-Car H3 ES1.x, V3M, V3H, and D3]
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>