ARM: dts: omap5: fix gpu_cm clock provider name

The clkctrl code searches for the parent clockdomain based on the name
of the CM provider node. The introduction of SGX node for omap5 made
the node name for the gpu_cm to be clock-controller. There is no
clockdomain named like this, so the lookup fails. Fix by changing
the node name properly.

Fixes: 394534cb ("ARM: dts: Configure sgx for omap5")
Signed-off-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>