net: stmmac: provide common stmmac_axi_blen_to_mask()

net: stmmac: provide common stmmac_axi_blen_to_mask()

Provide a common stmmac_axi_blen_to_mask() function to translate the
burst length array to the value for the AXI bus mode register, and use
it for dwmac, dwmac4 and dwxgmac2. Remove the now unnecessary
XGMAC_BLEN* definitions.

Note that stmmac_axi_blen_to_dma_mask() is coded to be more efficient
than the original three implementations, and verifies the contents of
the burst length array.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1vLfLR-0000000FMav-0VL6@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>