siemens: capricorn: move to cxg3 reference project with deneb board

We have many HW with capricorn i.MX8X boards. The difference in u-boot is
at all by the display of the LEDs.

* put upstream a reference project & board for DT and defconfig
* use the capricorn prefix outside the board/siemens/capricorn folder

Signed-off-by: Enrico Leto <enrico.leto@siemens.com>
Signed-off-by: Heiko Schocher <hs@denx.de>
diff --git a/arch/arm/mach-imx/imx8/Kconfig b/arch/arm/mach-imx/imx8/Kconfig
index 59d11b3..9a43bed 100644
--- a/arch/arm/mach-imx/imx8/Kconfig
+++ b/arch/arm/mach-imx/imx8/Kconfig
@@ -54,15 +54,8 @@
 	select BOARD_LATE_INIT
 	select IMX8QXP
 
-config TARGET_DENEB
-	bool "Support i.MX8QXP Capricorn Deneb board"
-	select BINMAN
-	select BOARD_LATE_INIT
-	select FACTORYSET
-	select IMX8QXP
-
-config TARGET_GIEDI
-	bool "Support i.MX8QXP Capricorn Giedi board"
+config TARGET_CAPRICORN
+	bool "Support i.MX8QXP Capricorn board"
 	select BINMAN
 	select BOARD_LATE_INIT
 	select FACTORYSET