rockchip: ringneck-px30: enforce ENV_IS_NOWHERE with Kconfig select

Instead of letting the compiler error out if CONFIG_ENV_IS_NOWHERE is
not selected by the user, let's just enforce it when the user builds for
Ringneck PX30 so that no check needs to be performed by the compiler and
the configuration is always valid.

Suggested-by: Tom Rini <trini@konsulko.com>
Cc: Quentin Schulz <foss+uboot@0leil.net>
Signed-off-by: Quentin Schulz <quentin.schulz@theobroma-systems.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/board/theobroma-systems/ringneck_px30/Kconfig b/board/theobroma-systems/ringneck_px30/Kconfig
index 24d9480..c33253b 100644
--- a/board/theobroma-systems/ringneck_px30/Kconfig
+++ b/board/theobroma-systems/ringneck_px30/Kconfig
@@ -11,6 +11,7 @@
 
 config BOARD_SPECIFIC_OPTIONS # dummy
 	def_bool y
+	select ENV_IS_NOWHERE
 
 config ENV_SIZE
 	default 0x3000
diff --git a/board/theobroma-systems/ringneck_px30/ringneck-px30.c b/board/theobroma-systems/ringneck_px30/ringneck-px30.c
index 47d1a40..bb1bb4a 100644
--- a/board/theobroma-systems/ringneck_px30/ringneck-px30.c
+++ b/board/theobroma-systems/ringneck_px30/ringneck-px30.c
@@ -118,10 +118,6 @@
 	return CONFIG_SYS_MMC_ENV_DEV;
 }
 
-#if !IS_ENABLED(CONFIG_ENV_IS_NOWHERE)
-#error Please enable CONFIG_ENV_IS_NOWHERE
-#endif
-
 enum env_location arch_env_get_location(enum env_operation op, int prio)
 {
 	const char *boot_device =
diff --git a/configs/ringneck-px30_defconfig b/configs/ringneck-px30_defconfig
index 91706d8..e9234ef 100644
--- a/configs/ringneck-px30_defconfig
+++ b/configs/ringneck-px30_defconfig
@@ -68,7 +68,6 @@
 CONFIG_OF_LIVE=y
 CONFIG_OF_SPL_REMOVE_PROPS="interrupt-parent assigned-clocks assigned-clock-rates assigned-clock-parents"
 CONFIG_ENV_OVERWRITE=y
-CONFIG_ENV_IS_NOWHERE=y
 CONFIG_ENV_IS_IN_MMC=y
 CONFIG_SYS_RELOC_GD_ENV_ADDR=y
 CONFIG_SPL_DM_SEQ_ALIAS=y