mx6cuboxi: Fix Ethernet PHY detection problem

mx6cuboxi: Fix Ethernet PHY detection problem

mx6cuboxi sometimes fails to recognize the Ethernet PHY:

Net:   Phy 0 not found

The explanation for this behavior comes from from Rabeeh Khoury:

"The LED_ACT pin on the carrier-one boards had a pull down that
forces the phy address to 0x0; where on CuBox-i and the production
HummingBoard that pin is connected directly to LED that depending
on the pull down strength of the LED it might be sampled as '0' or '1' thus
the phy address might appear as either address 0x0 or 0x4."

"This is AR8035 implementation; in reset stage the LED pin is configured as
input, and pull up/down does matter. In this case it configures the PHY
address.

After reset is deasserted the same LED pin becomes output and then
according to the previous pull/up it should be active high/low"

One way to properly fix this behavior is to place external pull-up/down
resistors in the LED line, but from a software standpoint we can fix it
by telling phy_find_by_mask() to scan the PHY at addresses
0x0 and 0x4.

Reported-by: Vagrant Cascadian <vagrant@aikidev.net>
Signed-off-by: Rabeeh Khoury <rabeeh@solid-run.com>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Stefano Babic <sbabic@denx.de>
Reviewed-by: Tom Rini <trini@konsulko.com>
Tested-By: Vagrant Cascadian <vagrant@aikidev.net>