[ARM] fix naming of MODULE_START / MODULE_END

As of 73bdf0a60e607f4b8ecc5aec597105976565a84f, the kernel needs
to know where modules are located in the virtual address space.
On ARM, we located this region between MODULE_START and MODULE_END.
Unfortunately, everyone else calls it MODULES_VADDR and MODULES_END.
Update ARM to use the same naming, so is_vmalloc_or_module_addr()
can work properly.  Also update the comment on mm/vmalloc.c to
reflect that ARM also places modules in a separate region from the
vmalloc space.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/kernel/module.c b/arch/arm/kernel/module.c
index 9203ba7..b8d965d 100644
--- a/arch/arm/kernel/module.c
+++ b/arch/arm/kernel/module.c
@@ -26,12 +26,12 @@
 /*
  * The XIP kernel text is mapped in the module area for modules and
  * some other stuff to work without any indirect relocations.
- * MODULE_START is redefined here and not in asm/memory.h to avoid
+ * MODULES_VADDR is redefined here and not in asm/memory.h to avoid
  * recompiling the whole kernel when CONFIG_XIP_KERNEL is turned on/off.
  */
 extern void _etext;
-#undef MODULE_START
-#define MODULE_START	(((unsigned long)&_etext + ~PGDIR_MASK) & PGDIR_MASK)
+#undef MODULES_VADDR
+#define MODULES_VADDR	(((unsigned long)&_etext + ~PGDIR_MASK) & PGDIR_MASK)
 #endif
 
 #ifdef CONFIG_MMU
@@ -43,7 +43,7 @@
 	if (!size)
 		return NULL;
 
-	area = __get_vm_area(size, VM_ALLOC, MODULE_START, MODULE_END);
+	area = __get_vm_area(size, VM_ALLOC, MODULES_VADDR, MODULES_END);
 	if (!area)
 		return NULL;