arm64: dts: ti: k3-am62-lp-sk: Modify frequencies according to PHY

commit 3748f53901315f7f2cc0823ba13b4505298acfdd from
git://git.ti.com/ti-linux-kernel/ti-linux-kernel.git



With PHY being tuned at a optimal tuning point, set the controller
frequency to operate at higher frequency possible and set the SPI
bus frequency to 25 MHz and respective read-delay.

Signed-off-by: Santhosh Kumar K <s-k6@ti.com>
Signed-off-by: Xulin Sun <xulin.sun@windriver.com>