driver/ldpaa_eth: Update ldpaa ethernet driver

Fix flush_dcache_range() input parameter to use start and end addresses.
Change ethernet interface name to DPNI. Update entry criteria for
ldpaa_eth_stop. Ethernet stack first stop the device before performing
next operation. At the time of Ethernet driver registration,
net_dev->state is set as ETH_STATE_INIT So take care net_dev->state as
ETH_STATE_INIT in ldpaa_eth_stop.

Undef CONFIG_PHYLIB temorarily because ldpaa_eth driver currently does
not support PHYLIB.

Instead of clearing pull descriptor one time, clear it before issuing any
volatile dequeue command.

Volatile command does not return frame immidiately, wait till a frame
is available in DQRR. This frame can be valid or expired.

Flush buffer before releasing to BMan ensure the core does not have any
cachelines that the WRIOP will DMA to.

Signed-off-by: Prabhakar Kushwaha <prabhakar@freescale.com>
Signed-off-by: pankaj chauhan <pankaj.chauhan@freescale.com>
Signed-off-by: Roy Pledge <Roy.Pledge@freescale.com>
Signed-off-by: York Sun <yorksun@freescale.com>