clk: at91: sam9x60: support only two programmable clocks

According to datasheet (Chapter 29.16.13, PMC Programmable Clock Register)
there are only two programmable clocks on SAM9X60.

Fixes: 01e2113d ("clk: at91: add sam9x60 pmc driver")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/1602686072-28296-1-git-send-email-claudiu.beznea@microchip.com


Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>