drm/mgag200:remove rebundant word "or" in comments

there is a repeated word "or" in comments, so remove it.

Signed-off-by: shaomin Deng <[e-mail]>
Signed-off-by: Thomas Zimmermann <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/mgag200/mgag200_reg.h

···
 #define MGAREG_SRCORG		0x2cb4
 #define MGAREG_DSTORG		0x2cb8
 
-/* add or or this to one of the previous "power registers" to start
+/* add or this to one of the previous "power registers" to start
    the drawing engine */
 
 #define MGAREG_EXEC		0x0100