clk: at91: sama7g5: add 5th divisor for mck0 layout and characteristics

This SoC has the 5th divisor for the mck0 master clock.
Adapt the characteristics accordingly.

Reported-by: Mihai Sain <mihai.sain@microchip.com>
Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/1605800597-16720-6-git-send-email-claudiu.beznea@microchip.com


Signed-off-by: Stephen Boyd <sboyd@kernel.org>