clk: mmp2: Fix bit masks for LCDC I/O and pixel clocks

They were reversed because I read the datasheet upside down.
Actually there is no datasheet, but I ended up understanding the
comments in Open Firmware driver wrong.

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Link: https://lkml.kernel.org/r/20200309194254.29009-18-lkundrak@v3.sk
Signed-off-by: Stephen Boyd <sboyd@kernel.org>