clk: at91: sam9x60: remove the parsing of atmel, main-osc-bypass

Remove the parsing of atmel,main-osc-bypass DT property as the SAM9X60
have no support for crystal oscillator bypass. Setting this bit might
affect the device functionality.

Fixes: a6486228 ("clk: at91: sam9x60: add support compatible with CCF")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>