arm64: dts: rockchip: Fix name for UART pin header on qnap-ts433

I typoed the pin header name when copying it from my notes on paper.

Fixes: 9da1c03 ("arm64: dts: rockchip: Add basic support for QNAP TS-433")
Signed-off-by: Uwe Kleine-König <ukleinek@debian.org>
Link: https://lore.kernel.org/r/20240301163201.559787-2-ukleinek@debian.org
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

Author: ukleinek

arch/arm64/boot/dts/rockchip/rk3568-qnap-ts433.dts

@@ -76,7 +76,7 @@
 };
 
 /*
- * Pins available on CN2 connector at TTL voltage level (3V3).
+ * Pins available on CN3 connector at TTL voltage level (3V3).
  * ,_  _.
  * |1234|  1=TX 2=VCC
  * `----'  3=RX 4=GND