net: mvneta: replace MVNETA_CPU_D_CACHE_LINE_SIZE with L1_CACHE_BYTES

The mvneta is also used in some Marvell berlin family SoCs which may
have 64bytes cacheline size. Replace the MVNETA_CPU_D_CACHE_LINE_SIZE
usage with L1_CACHE_BYTES.

And since dma_alloc_coherent() is always cacheline size aligned, so
remove the align checks.

Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>