rockchip: firefly-px30: Fix the MACRO for CONFIG_DEBUG_UART2_CHANNEL

The Macro has update without update the defconfig, update the defconfig
to make Mcaro correct.

Fixes: ec4fafdf1f ("rockchip: px30: Rename CONFIG_DEBUG_UART2_CHANNEL to...")
Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/configs/firefly-px30_defconfig b/configs/firefly-px30_defconfig
index fa4ac75..5171bf8 100644
--- a/configs/firefly-px30_defconfig
+++ b/configs/firefly-px30_defconfig
@@ -32,7 +32,7 @@
 CONFIG_SPL_ATF=y
 # CONFIG_TPL_FRAMEWORK is not set
 # CONFIG_CMD_BOOTD is not set
-CONFIG_DEBUG_UART2_CHANNEL=1
+CONFIG_DEBUG_UART_CHANNEL=1
 # CONFIG_CMD_ELF is not set
 # CONFIG_CMD_IMI is not set
 # CONFIG_CMD_XIMG is not set