staging: sm750fb: Fix bugs introduced by early commits

Early commit 30ca5cb6 ("staging: sm750fb: change definition of
PANEL_PLANE_TL fields") and 27b047bb ("staging: sm750fb: change
definition of PANEL_PLANE_BR fields") modify the register bit fields
definitions. But the modifications are wrong, because the bit mask of
"bit field 10:0" is not 0xeff, but 0x7ff. The wrong definition bugs
makes display very strange.
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Cc: stable <stable@vger.kernel.org> # 4.6+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/sm750fb/ddk750_reg.h

@@ -601,13 +601,13 @@
 
 #define PANEL_PLANE_TL                                0x08001C
 #define PANEL_PLANE_TL_TOP_SHIFT                      16
-#define PANEL_PLANE_TL_TOP_MASK                       (0xeff << 16)
-#define PANEL_PLANE_TL_LEFT_MASK                      0xeff
+#define PANEL_PLANE_TL_TOP_MASK                       (0x7ff << 16)
+#define PANEL_PLANE_TL_LEFT_MASK                      0x7ff
 
 #define PANEL_PLANE_BR                                0x080020
 #define PANEL_PLANE_BR_BOTTOM_SHIFT                   16
-#define PANEL_PLANE_BR_BOTTOM_MASK                    (0xeff << 16)
-#define PANEL_PLANE_BR_RIGHT_MASK                     0xeff
+#define PANEL_PLANE_BR_BOTTOM_MASK                    (0x7ff << 16)
+#define PANEL_PLANE_BR_RIGHT_MASK                     0x7ff
 
 #define PANEL_HORIZONTAL_TOTAL                        0x080024
 #define PANEL_HORIZONTAL_TOTAL_TOTAL_SHIFT            16