ARM: l2x0/pl310: Refactor Kconfig to be more maintainable

Making CACHE_L2X0 depend on (huge list of MACH_ and ARCH_ configs)
is bothersome to maintain and likely to lead to merge conflicts.

This patch moves the knowledge of which platforms have a L2x0 or
PL310 cache controller to the individual machines.  To enable this,
a new MIGHT_HAVE_CACHE_L2X0 config option is introduced to allow
machines to indicate that they may have such a cache controller
independently of each other.

Boards/SoCs which cannot reliably operate without the L2 cache
controller support will need to select CACHE_L2X0 directly from
their own Kconfigs instead.  This applies to some TrustZone-enabled
boards where Linux runs in the Normal World, for example.

Signed-off-by: Dave Martin <dave.martin@linaro.org>
Acked-by: Anton Vorontsov <cbouatmailru@gmail.com>
        (for cns3xxx)
Acked-by: Tony Lindgren <tony@atomide.com>
        (for omap)
Acked-by: Shawn Guo <shawn.guo@linaro.org>
        (for imx)
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
        (for exynos)
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
        (for imx)
Acked-by: Olof Johansson <olof@lixom.net>
        (for tegra)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 44789ef..16a4b9e 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -344,6 +344,7 @@
 	select CPU_V7
 	select GENERIC_CLOCKEVENTS
 	select HAVE_ARM_SCU
+	select MIGHT_HAVE_CACHE_L2X0
 	select USE_OF
 	help
 	  Support for the Calxeda Highbank SoC based boards.
@@ -361,6 +362,7 @@
 	select CPU_V6K
 	select GENERIC_CLOCKEVENTS
 	select ARM_GIC
+	select MIGHT_HAVE_CACHE_L2X0
 	select MIGHT_HAVE_PCI
 	select PCI_DOMAINS if PCI
 	help
@@ -381,6 +383,7 @@
 	select GENERIC_CLOCKEVENTS
 	select CLKDEV_LOOKUP
 	select GENERIC_IRQ_CHIP
+	select MIGHT_HAVE_CACHE_L2X0
 	select USE_OF
 	select ZONE_DMA
 	help
@@ -633,6 +636,7 @@
 	select GENERIC_GPIO
 	select HAVE_CLK
 	select HAVE_SCHED_CLOCK
+	select MIGHT_HAVE_CACHE_L2X0
 	select ARCH_HAS_CPUFREQ
 	help
 	  This enables support for NVIDIA Tegra based systems (Tegra APX,
@@ -703,6 +707,7 @@
 	select CLKDEV_LOOKUP
 	select HAVE_MACH_CLKDEV
 	select GENERIC_CLOCKEVENTS
+	select MIGHT_HAVE_CACHE_L2X0
 	select NO_IOPORT
 	select SPARSE_IRQ
 	select MULTI_IRQ_HANDLER
@@ -904,6 +909,7 @@
 	select CLKDEV_LOOKUP
 	select ARCH_REQUIRE_GPIOLIB
 	select ARCH_HAS_CPUFREQ
+	select MIGHT_HAVE_CACHE_L2X0
 	help
 	  Support for ST-Ericsson's Ux500 architecture
 
@@ -914,6 +920,7 @@
 	select CPU_ARM926T
 	select CLKDEV_LOOKUP
 	select GENERIC_CLOCKEVENTS
+	select MIGHT_HAVE_CACHE_L2X0
 	select ARCH_REQUIRE_GPIOLIB
 	help
 	  Support for the Nomadik platform by ST-Ericsson
@@ -973,6 +980,7 @@
 	select ARM_GIC
 	select ARM_AMBA
 	select ICST
+	select MIGHT_HAVE_CACHE_L2X0
 	select USE_OF
 	help
 	  Support for Xilinx Zynq ARM Cortex A9 Platform