arm64: dts: ti: k3-am642-phyboard-electra-peb-c-010: Fix icssg-prueth schema warning

arm64: dts: ti: k3-am642-phyboard-electra-peb-c-010: Fix icssg-prueth schema warning

Reduce length of dma-names and dmas properties for icssg1-ethernet
node to comply with ti,icssg-prueth schema constraints. The previous
entries exceeded the allowed count and triggered dtschema warnings
during validation.

Fixes: e53fbf955ea7 ("arm64: dts: ti: k3-am642-phyboard-electra: Add PEB-C-010 Overlay")
Signed-off-by: Wadim Egorov <w.egorov@phytec.de>
Link: https://patch.msgid.link/20251127122733.2523367-1-w.egorov@phytec.de
Signed-off-by: Nishanth Menon <nm@ti.com>