nvidiafb: ensure that CRTC registers are accessible

- Ensure that CRTC registers are accessible by unlocking them on set_par(),
otherwise i2c reading will fail.

- The function nvidia_vga_protect(), does not protect the VGA registers, but
turns off the screen. Rename it to nvidia_screen_off().

Signed-off-by: Antonino Daplas <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/video/nvidia/nvidia.c

···
    return tweak;
 }
 
-static void nvidia_vga_protect(struct nvidia_par *par, int on)
+static void nvidia_screen_off(struct nvidia_par *par, int on)
 {
 	unsigned char tmp;
 
···
 		NVLockUnlock(par, 0);
 	}
 
-	nvidia_vga_protect(par, 1);
+	nvidia_screen_off(par, 1);
 
 	nvidia_write_regs(par, &par->ModeReg);
 	NVSetStartAddress(par, 0);
···
 
 	par->cursor_reset = 1;
 
-	nvidia_vga_protect(par, 0);
+	nvidia_screen_off(par, 0);
 
 #ifdef CONFIG_BOOTX_TEXT
 	/* Update debug text engine */
···
 			     info->var.bits_per_pixel, info->fix.line_length);
 #endif
 
+	NVLockUnlock(par, 0);
 	NVTRACE_LEAVE();
 	return 0;
 }