[PATCH] drm: count reaches -1, tested 0

[Roel Kluin <roel.kluin@gmail.com>]

With a postfix decrement count will reach -1 rather than 0,
subsequent tests fail.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
---
diff --git a/drivers/gpu/drm/via/via_dma.c b/drivers/gpu/drm/via/via_dma.c
index 7a339db..600315c 100644
--- a/drivers/gpu/drm/via/via_dma.c
+++ b/drivers/gpu/drm/via/via_dma.c
@@ -481,9 +481,9 @@ static int via_wait_idle(drm_via_private_t * dev_priv)
 {
 	int count = 10000000;
 
-	while (!(VIA_READ(VIA_REG_STATUS) & VIA_VR_QUEUE_BUSY) && count--);
+	while (!(VIA_READ(VIA_REG_STATUS) & VIA_VR_QUEUE_BUSY) && --count);
 
-	while (count-- && (VIA_READ(VIA_REG_STATUS) &
+	while (--count && (VIA_READ(VIA_REG_STATUS) &
 			   (VIA_CMD_RGTR_BUSY | VIA_2D_ENG_BUSY |
 			    VIA_3D_ENG_BUSY))) ;
 	return count;
@@ -705,7 +705,7 @@ static int via_cmdbuf_size(struct drm_device *dev, void *data, struct drm_file *
 	switch (d_siz->func) {
 	case VIA_CMDBUF_SPACE:
 		while (((tmp_size = via_cmdbuf_space(dev_priv)) < d_siz->size)
-		       && count--) {
+		       && --count) {
 			if (!d_siz->wait) {
 				break;
 			}
@@ -717,7 +717,7 @@ static int via_cmdbuf_size(struct drm_device *dev, void *data, struct drm_file *
 		break;
 	case VIA_CMDBUF_LAG:
 		while (((tmp_size = via_cmdbuf_lag(dev_priv)) > d_siz->size)
-		       && count--) {
+		       && --count) {
 			if (!d_siz->wait) {
 				break;
 			}