pinctrl: aspeed: Correct comment that is no longer true

We have handled the GFX register case for quite some time now.

Cc: Johnny Huang <johnny_huang@aspeedtech.com>
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Acked-by: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/r/20190628023838.15426-6-andrew@aj.id.auSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/aspeed/pinctrl-aspeed.h

@@ -244,8 +244,7 @@
  * opposed to naming them e.g. PINMUX_CTRL_[0-9]). Further, signal expressions
  * reference registers beyond those dedicated to pinmux, such as the system
  * reset control and MAC clock configuration registers. The AST2500 goes a step
- * further and references registers in the graphics IP block, but that isn't
- * handled yet.
+ * further and references registers in the graphics IP block.
  */
 #define SCU2C           0x2C /* Misc. Control Register */
 #define SCU3C           0x3C /* System Reset Control/Status Register */