net: xilinx: axienet: Correct BD length masks to match AXIDMA IP spec

net: xilinx: axienet: Correct BD length masks to match AXIDMA IP spec

The XAXIDMA_BD_CTRL_LENGTH_MASK and XAXIDMA_BD_STS_ACTUAL_LEN_MASK
macros were defined as 0x007FFFFF (23 bits), but the AXI DMA IP
product guide (PG021) specifies the buffer length field as bits 25:0
(26 bits). Update both masks to match the IP documentation.

In practice this had no functional impact, since Ethernet frames are
far smaller than 2^23 bytes and the extra bits were always zero, but
the masks should still reflect the hardware specification.

Fixes: 8a3b7a252dca ("drivers/net/ethernet/xilinx: added Xilinx AXI Ethernet driver")
Signed-off-by: Suraj Gupta <suraj.gupta2@amd.com>
Reviewed-by: Sean Anderson <sean.anderson@linux.dev>
Link: https://patch.msgid.link/20260327073238.134948-2-suraj.gupta2@amd.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>