arch: arm: dts: k3-am69-r5-sk: Add missing fss range

arch: arm: dts: k3-am69-r5-sk: Add missing fss range

Upstream DTS added explicit ranges to the fss node.  It did not include the
32 bit memory space needed by the R5 to access OSPI.  With the upstream DTS
sync, OSPI boot no longer works.

Adding the missing range here. It is also being added in the upstream DTS,
so after the next upstream DTS sync, this patch can be removed. See
f062a015f4 (arm64: dts: ti: k3-j784s4: Use exact ranges for FSS node)

Fixes: 5024a96db8e ("Subtree merge tag 'v6.10-dts' of devicetree-rebasing repo [1] into dts/upstream")
Signed-off-by: Jonathan Humphreys <j-humphreys@ti.com>