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

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: 96cbdfdd3ac2 ("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>