zynq: kconfig: move board select menu and common settings

Becuase the board select menu in arch/arm/Kconfig is too big,
move the Zynq board select menu to zynq/Kconfig.

Consolidate also common settings (CONFIG_SYS_CPU="armv7" and
CONFIG_SYS_SOC="zynq").

Refactor board/xilinx/zynq/MAINTAINERS too.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Tested-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 71757e7..cac9143 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -668,17 +668,8 @@
 config TARGET_VF610TWR
 	bool "Support vf610twr"
 
-config TARGET_ZYNQ_MICROZED
-	bool "Support zynq_microzed"
-
-config TARGET_ZYNQ_ZC70X
-	bool "Support zynq_zc70x"
-
-config TARGET_ZYNQ_ZC770
-	bool "Support zynq_zc770"
-
-config TARGET_ZYNQ_ZED
-	bool "Support zynq_zed"
+config ZYNQ
+	bool "Xilinx Zynq Platform"
 
 config TARGET_MEDCOM_WIDE
 	bool "Support medcom-wide"
@@ -784,6 +775,7 @@
 
 endchoice
 
+source "arch/arm/cpu/armv7/zynq/Kconfig"
 source "board/8dtech/eco5pk/Kconfig"
 source "board/aristainetos/Kconfig"
 source "board/Barix/ipam390/Kconfig"
@@ -1012,7 +1004,6 @@
 source "board/wandboard/Kconfig"
 source "board/woodburn/Kconfig"
 source "board/xaeniax/Kconfig"
-source "board/xilinx/zynq/Kconfig"
 source "board/zipitz2/Kconfig"
 
 endmenu