Revert "net: stmmac: Specify hardware capability value when FIFO size isn't specified"

This reverts commit 8865d226, which caused breakage for platforms
which are not using xgmac2 or gmac4. Only these two cores have the
capability of providing the FIFO sizes from hardware capability fields
(which are provided in priv->dma_cap.[tr]x_fifo_size.)

All other cores can not, which results in these two fields containing
zero. We also have platforms that do not provide a value in
priv->plat->[tr]x_fifo_size, resulting in these also being zero.

This causes the new tests introduced by the reverted commit to fail,
and produce e.g.:

	stmmaceth f0804000.eth: Can't specify Rx FIFO size

An example of such a platform which fails is QEMU's npcm750-evb.
This uses dwmac1000 which, as noted above, does not have the capability
to provide the FIFO sizes from hardware.

Therefore, revert the commit to maintain compatibility with the way
the driver used to work.

Reported-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/4e98f967-f636-46fb-9eca-d383b9495b86@roeck-us.net


Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Tested-by: Steven Price <steven.price@arm.com>
Fixes: 8865d226 ("net: stmmac: Specify hardware capability value when FIFO size isn't specified")
Link: https://patch.msgid.link/E1tfeyR-003YGJ-Gb@rmk-PC.armlinux.org.uk


Signed-off-by: Paolo Abeni <pabeni@redhat.com>