sparc: Fix bus type probing for ESP and LE devices.

If there is a dummy "espdma" or "ledma" parent device above ESP scsi
or LE ethernet device nodes, we have to match the bus as SBUS.

Otherwise the address and size cell counts are wrong and we don't
calculate the final physical device resource values correctly at all.

Commit 5280267c

 ("sparc: Fix handling
of LANCE and ESP parent nodes in of_device.c") was meant to fix this
problem, but that only influences the inner loop of
build_device_resources().  We need this logic to also kick in at the
beginning of build_device_resources() as well, when we make the first
attempt to determine the device's immediate parent bus type for 'reg'
property element extraction.

Based almost entirely upon a patch by Friedrich Oslage.

Tested-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: David S. Miller <davem@davemloft.net>