ARM: dts: at91: sam9x60ek: remove bypass property

atmel,osc-bypass property sets the bit 1 at main oscillator register.
On SAM9X60 this bit is not valid according to datasheet (chapter
28.16.9 PMC Clock Generator Main Oscillator Register).

Fixes: 1e5f532c ("ARM: dts: at91: sam9x60: add device tree for soc and board")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Cc: Marco Cardellini <marco.cardellini@microchip.com>
Link: https://lore.kernel.org/r/1606903025-14197-2-git-send-email-claudiu.beznea@microchip.com