ARM: dts: Fix the name of supplies for smsc911x shared by OMAP

drivers/net/ethernet/smsc/smsc911x.c is expecting supplies named
"vdd33a" and "vddvario". Currently the shared DTS file provides
"vmmc" and "vmmc_aux", and the supply lookup will fail:

smsc911x 2c000000.ethernet: Looking up vdd33a-supply from device tree
smsc911x 2c000000.ethernet: Looking up vdd33a-supply property in node /ocp/gpmc@6e000000/ethernet@gpmc failed
smsc911x 2c000000.ethernet: Looking up vddvario-supply from device tree
smsc911x 2c000000.ethernet: Looking up vddvario-supply property in node /ocp/gpmc@6e000000/ethernet@gpmc failed

Fix it!

Looks like commmit 6b2978ac (ARM: dts: Shared file for omap GPMC
connected smsc911x) made the problem more visible by moving the smc911x
configuration from the omap3-igep0020.dts file to the generic file.
But it seems we've had this problem since commit d72b4415
(ARM: dts: omap3-igep0020: Add SMSC911x LAN chip support).

Tested on OMAP3 Overo platform.

Signed-off-by: Florian Vaussard <florian.vaussard@epfl.ch>
[tony@atomide.com: updated comments for the commits causing the problem]
Signed-off-by: Tony Lindgren <tony@atomide.com>