ARM: 7758/1: introduce config HAS_BANDGAP

Bandgap is a device used to measure temperature on electronic
equipments.  It is widely used in digital integrated circuits.  It is
based on the dependency between silicon voltage and temperature.

This patch introduce HAS_BANDGAP config entry.  This config is a boolean
value so that arch code can flag if they feature a bandgap device.

This config entry follows the same idea behind ARCH_HAS_CPUFREQ.

Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-omap@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: NFabio Stevam <festevam@gmail.com>
Acked-by: NTony Lindgren <tony@atomide.com>
Acked-by: NAmit Daniel Kachhap <amit.daniel@samsung.com>
Signed-off-by: NEduardo Valentin <eduardo.valentin@ti.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

arch/arm/Kconfig

@@ -174,6 +174,9 @@ config ARCH_HAS_CPUFREQ
 	  and that the relevant menu configurations are displayed for
 	  it.
 
+config ARCH_HAS_BANDGAP
+	bool
+
 config GENERIC_HWEIGHT
 	bool
 	default y

arch/arm/mach-omap2/Kconfig

@@ -4,6 +4,7 @@ config ARCH_OMAP
 config ARCH_OMAP2PLUS
 	bool "TI OMAP2/3/4/5 SoCs with device tree support" if (ARCH_MULTI_V6 || ARCH_MULTI_V7)
 	select ARCH_HAS_CPUFREQ
+	select ARCH_HAS_BANDGAP
 	select ARCH_HAS_HOLES_MEMORYMODEL
 	select ARCH_OMAP
 	select ARCH_REQUIRE_GPIOLIB