feat(st): update STM32MP DT files

This is an alignment with Linux DT files that have been merged in
stm32 tree [1], and will be in Linux 6.7.
The /omit-if-no-ref/ in overlay files are now removed, as already in
pinctrl files.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/atorgue/stm32.git

Signed-off-by: Yann Gautier <yann.gautier@st.com>
Change-Id: Iab94b0ba7a4a0288ca53d1ae57ab590566967415
diff --git a/fdts/stm32mp251.dtsi b/fdts/stm32mp251.dtsi
index 821eb49..f55a3b9 100644
--- a/fdts/stm32mp251.dtsi
+++ b/fdts/stm32mp251.dtsi
@@ -67,7 +67,7 @@
 		      <0x0 0x4ac60000 0x0 0x2000>;
 	};
 
-	timer: timer {
+	timer {
 		compatible = "arm,armv8-timer";
 		interrupt-parent = <&intc>;
 		interrupts = <GIC_PPI 13 (GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,