Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
diff --git a/drivers/video/matrox/matroxfb_base.c b/drivers/video/matrox/matroxfb_base.c
index 5ce6fa6..44bf8d4 100644
--- a/drivers/video/matrox/matroxfb_base.c
+++ b/drivers/video/matrox/matroxfb_base.c
@@ -621,7 +621,7 @@
 		var->yoffset = var->yres_virtual - var->yres;
 
 	if (bpp == 16 && var->green.length == 5) {
-		bpp--; /* an artifical value - 15 */
+		bpp--; /* an artificial value - 15 */
 	}
 
 	for (rgbt = table; rgbt->bpp < bpp; rgbt++);