offb: Fix bug in calculating requested vram size

We used to try to request 8 times more vram than needed, which would
fail if the card has a too small BAR (observed with qemu & kvm).

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: stable@kernel.org
diff --git a/drivers/video/offb.c b/drivers/video/offb.c
index cb163a5..915acae 100644
--- a/drivers/video/offb.c
+++ b/drivers/video/offb.c
@@ -381,7 +381,7 @@
 				int pitch, unsigned long address,
 				int foreign_endian, struct device_node *dp)
 {
-	unsigned long res_size = pitch * height * (depth + 7) / 8;
+	unsigned long res_size = pitch * height;
 	struct offb_par *par = &default_par;
 	unsigned long res_start = address;
 	struct fb_fix_screeninfo *fix;