driver net: cpsw: Convert pr_*() to dev_*() calls

Convert all pr_*() calls to dev_*() calls.
No functional changes.

Signed-off-by: George Cherian <george.cherian@ti.com>
Reviewed-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>