fbdev: viafb: use new array-copying-wrapper

viafbdev.c utilizes memdup_user() to copy an array from userspace.

There is a new wrapper, specifically designed for copying arrays. Use
this one instead.

Suggested-by: Dave Airlie <[e-mail]>
Signed-off-by: Philipp Stanner <[e-mail]>
Signed-off-by: Helge Deller <[e-mail]>

drivers/video/fbdev/via/viafbdev.c

···
 		break;
 
 	case VIAFB_SET_GAMMA_LUT:
-		viafb_gamma_table = memdup_user(argp, 256 * sizeof(u32));
+		viafb_gamma_table = memdup_array_user(argp, 256, sizeof(u32));
 		if (IS_ERR(viafb_gamma_table))
 			return PTR_ERR(viafb_gamma_table);
 		viafb_set_gamma_table(viafb_bpp, viafb_gamma_table);