m68k: rename global variable vmalloc_end to m68k_vmalloc_end

On SUN3, m68k defines macro VMALLOC_END as unsigned long variable
vmalloc_end which is adjusted from mmu_emu_init().  This becomes
problematic if a local variables vmalloc_end is defined in some
function (not very unlikely) and VMALLOC_END is used in the function -
the function thinks its referencing the global VMALLOC_END value but
would be referencing its own local vmalloc_end variable.

Rename the global variable to m68k_vmlloc_end which is much less
likely to be used as local variable name.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Roman Zippel <zippel@linux-m68k.org>

arch/m68k/include/asm/pgtable_mm.h

@@ -83,9 +83,9 @@
 #define VMALLOC_START (((unsigned long) high_memory + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1))
 #define VMALLOC_END KMAP_START
 #else
-extern unsigned long vmalloc_end;
+extern unsigned long m68k_vmalloc_end;
 #define VMALLOC_START 0x0f800000
-#define VMALLOC_END vmalloc_end
+#define VMALLOC_END m68k_vmalloc_end
 #endif /* CONFIG_SUN3 */
 
 /* zero page used for uninitialized stuff */

arch/m68k/sun3/mmu_emu.c

@@ -45,8 +45,8 @@
 ** Globals
 */
 
-unsigned long vmalloc_end;
-EXPORT_SYMBOL(vmalloc_end);
+unsigned long m68k_vmalloc_end;
+EXPORT_SYMBOL(m68k_vmalloc_end);
 
 unsigned long pmeg_vaddr[PMEGS_NUM];
 unsigned char pmeg_alloc[PMEGS_NUM];
@@ -172,8 +172,8 @@ void mmu_emu_init(unsigned long bootmem_end)
 #endif
 			// the lowest mapping here is the end of our
 			// vmalloc region
-			if(!vmalloc_end)
-				vmalloc_end = seg;
+			if (!m68k_vmalloc_end)
+				m68k_vmalloc_end = seg;
 
 			// mark the segmap alloc'd, and reserve any
 			// of the first 0xbff pages the hardware is