ARM: Allow Kconfig to control the definition of NR_BANKS

Move the sizing of NR_BANKS to a Kconfig control instead of selecting
it in a header file depending on platform selection.  This allows new
additions to its dependencies to be handled more gracefully.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/include/asm/setup.h

@@ -192,11 +192,7 @@ static const struct tagtable __tagtable_##fn __tag = { tag, fn }
 /*
  * Memory map description
  */
-#ifdef CONFIG_ARCH_EP93XX
-# define NR_BANKS 16
-#else
-# define NR_BANKS 8
-#endif
+#define NR_BANKS	CONFIG_ARM_NR_BANKS
 
 struct membank {
 	phys_addr_t start;