arm64: dts: ti: k3-j784s4-j742s2-main-common: Fix serdes_ln_ctrl reg-masks

Commit under Fixes added the 'idle-states' property for SERDES4 lane muxes
without defining the corresponding register offsets and masks for it in the
'mux-reg-masks' property within the 'serdes_ln_ctrl' node.

Fix this.

Fixes: 7287d423 ("arm64: dts: ti: k3-j784s4-main: Add system controller and SERDES lane mux")
Cc: stable@vger.kernel.org
Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com>
Link: https://lore.kernel.org/r/20250228053850.506028-1-s-vadapalli@ti.com


Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>