gma500: Mask out bits not part of the page table base address

Otherwise we can't ioremap the gtt and the screen gets garbled.
Signed-off-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/gma500/gtt.c

@@ -397,7 +397,7 @@ int psb_gtt_init(struct drm_device *dev, int resume)
 	/* The root resource we allocate address space from */
 	dev_priv->gtt_initialized = 1;
 
-	pg->gtt_phys_start = dev_priv->pge_ctl;
+	pg->gtt_phys_start = dev_priv->pge_ctl & PAGE_MASK;
 	
 	/*
 	 *	FIXME: video mmu has hw bug to access 0x0D0000000,