OMAP: Increase VMALLOC_END to allow 256MB RAM

This increases VMALLOC_END to 0x18000000, making room for 256MB
RAM with the default 128MB vmalloc region.

Note that after this patch there's no longer a hole between vmalloc
space and the beginning of IO space on omap2 as the first virtual
mapping starts at 0xd8000000.
Signed-off-by: Mans Rullgard <mans@mansr.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>

arch/arm/plat-omap/include/mach/vmalloc.h

@@ -17,5 +17,5 @@
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  */
-#define VMALLOC_END	  (PAGE_OFFSET + 0x17000000)
+#define VMALLOC_END	  (PAGE_OFFSET + 0x18000000)