arm64: dts: ti: k3-am62a7: Correct L2 cache size to 512KB

Per AM62Ax SoC datasheet[0] L2 cache is 512KB.

[0] https://www.ti.com/lit/gpn/am62a7

 Page 1.

Fixes: 5fc6b1b6 ("arm64: dts: ti: Introduce AM62A7 family of SoCs")
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Link: https://lore.kernel.org/r/20230320044935.2512288-2-vigneshr@ti.com


Signed-off-by: Nishanth Menon <nm@ti.com>