add new config to UART2

# Please enter the commit message for your changes. Lines starting
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# Date:      Tue Apr 8 12:10:22 2025 +0800
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# On branch master
# Changes to be committed:
#	modified:   KEIL/Rtc_Wakeup_Demo.uvprojx
#	modified:   Rtc_Wakeup_Demo.yct
#	modified:   app/main.c
#	modified:   board/linflexd_uart_config.c
#	modified:   board/linflexd_uart_config.h
#
# Changes not staged for commit:
#	modified:   KEIL/JLinkLog.txt
#	modified:   KEIL/Listings/Rtc_Wakeup_Demo.map
#	modified:   KEIL/Rtc_Wakeup_Demo.uvoptx
#	modified:   KEIL/Rtc_Wakeup_Demo.uvprojx
#
# Untracked files:
#	KEIL/Rtc_Wakeup_Demo.uvguix.tqnofc
#	backup.c
#
