soc: ixp4xx: Protect IXP4xx SoC drivers by ARCH_IXP4XX || COMPILE_TEST

The move of the IXP4xx SoC drivers exposed their config options on all
platforms.

Fix this by wrapping them inside an ARCH_IXP4XX or COMPILE_TEST block.

Link: https://lore.kernel.org/r/20190823090352.12243-1-linus.walleij@linaro.org
Fixes: fcf2d897 ("ARM: ixp4xx: Move NPE and QMGR to drivers/soc")
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>

drivers/soc/ixp4xx/Kconfig

 # SPDX-License-Identifier: GPL-2.0-only
+if ARCH_IXP4XX || COMPILE_TEST
+
 menu "IXP4xx SoC drivers"
 
 config IXP4XX_QMGR
@@ -15,3 +17,5 @@ config IXP4XX_NPE
 	  and is automatically selected by Ethernet and HSS drivers.
 
 endmenu
+
+endif