clk: renesas: r9a06g032: Fix UART clkgrp bitsel

clk: renesas: r9a06g032: Fix UART clkgrp bitsel

There are two UART clock groups, each having a mux to select its
upstream clock source. The register/bit definitions for accessing these
two muxes appear to have been reversed since introduction. Correct them
so as to match the hardware manual.

Fixes: 4c3d88526eba ("clk: renesas: Renesas R9A06G032 clock driver")

Signed-off-by: Ralph Siemsen <ralph.siemsen@linaro.org>
Reviewed-by: Phil Edworthy <phil.edworthy@renesas.com>
Link: https://lore.kernel.org/r/20220518182527.1693156-1-ralph.siemsen@linaro.org
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>