clk: vc3: Fix output clock mapping

According to Table 3. ("Output Source") in the 5P35023 datasheet,
the output clock mapping should be 0=REF, 1=SE1, 2=SE2, 3=SE3,
4=DIFF1, 5=DIFF2. But the code uses inverse. Fix this mapping issue.

Suggested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Closes: https://lore.kernel.org/all/CAMuHMdUHD+bEco=WYTYWsTAyRt3dTQQt4Xpaejss0Y2ZpLCMNg@mail.gmail.com/
Fixes: 6e9aff55

 ("clk: Add support for versa3 clock driver")
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20230824104812.147775-4-biju.das.jz@bp.renesas.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>