siemens: Move CONFIG_FACTORYSET to Kconfig

Introduce board/siemens/common/Kconfig and have it hold FACTORYSET to
start with.  Use select for this on the boards that need it.

Cc: Anatolij Gustschin <agust@denx.de>
Cc: Samuel Egli <samuel.egli@siemens.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/arch/arm/mach-omap2/am33xx/Kconfig b/arch/arm/mach-omap2/am33xx/Kconfig
index 23865d4..bd6b086 100644
--- a/arch/arm/mach-omap2/am33xx/Kconfig
+++ b/arch/arm/mach-omap2/am33xx/Kconfig
@@ -138,6 +138,7 @@
 	select DM
 	select DM_GPIO
 	select DM_SERIAL
+	select FACTORYSET
 	imply CMD_DM
 
 config TARGET_ETAMIN
@@ -146,6 +147,7 @@
 	select DM
 	select DM_GPIO
 	select DM_SERIAL
+	select FACTORYSET
 	imply CMD_DM
 
 config TARGET_PCM051
@@ -168,6 +170,7 @@
 	select DM
 	select DM_GPIO
 	select DM_SERIAL
+	select FACTORYSET
 	imply CMD_DM
 
 config TARGET_RASTABAN
@@ -176,6 +179,7 @@
 	select DM
 	select DM_GPIO
 	select DM_SERIAL
+	select FACTORYSET
 	imply CMD_DM
 
 config TARGET_RUT
@@ -184,6 +188,7 @@
 	select DM
 	select DM_GPIO
 	select DM_SERIAL
+	select FACTORYSET
 	imply CMD_DM
 
 config TARGET_THUBAN
@@ -192,6 +197,7 @@
 	select DM
 	select DM_GPIO
 	select DM_SERIAL
+	select FACTORYSET
 	imply CMD_DM
 
 config TARGET_PDU001