arm64: dts: rockchip: Fix headphones widget name on NanoPi M5

Fix the mismatch between the simple-audio-card routing table vs. widget
names, which caused the following error at boot preventing the sound
card from getting added:

[    6.625634] asoc-simple-card sound: ASoC: DAPM unknown pin Headphones
[    6.627247] asoc-simple-card sound: ASoC: Failed to add route HPOL -> Headphones(*)
[    6.627988] asoc-simple-card sound: ASoC: Failed to add route HPOR -> Headphones(*)

Fixes: 96cbdfd ("arm64: dts: rockchip: Add FriendlyElec NanoPi M5 support")
Cc: stable@vger.kernel.org
Signed-off-by: Alexey Charkov <alchark@gmail.com>
Link: https://patch.msgid.link/20251229-rk3576-sound-v1-1-2f59ef0d19b1@gmail.com
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

Author: alchark

arch/arm64/boot/dts/rockchip/rk3576-nanopi-m5.dts

@@ -211,7 +211,7 @@
 			"Headphones", "HPOR",
 			"IN1P", "Microphone Jack";
 		simple-audio-card,widgets =
-			"Headphone", "Headphone Jack",
+			"Headphone", "Headphones",
 			"Microphone", "Microphone Jack";
 
 		simple-audio-card,codec {