ARM: OMAP2+: clock data: Add dev-id for the omap-gpmc dummy fck

The GPMC code has been converted to a driver by the following commit:

 commit da496873
 Author: Afzal Mohammed <afzal@ti.com>
 Date:   Sun Sep 23 17:28:25 2012 -0600

   ARM: OMAP2+: gpmc: minimal driver support

It now requests a clock with con-id "fck" otherwise the probe will fails.

[    0.342010] omap-gpmc omap-gpmc: error: clk_get
[    0.346771] omap-gpmc: probe of omap-gpmc failed with error -2

Add the "omap-gmpc" dev-id and fck con-id to the already existing
gmpc-fck dummy clock.

Reported-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Benoit Cousson <b-cousson@ti.com>
Cc: Afzal Mohammed <afzal@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>