net/freescale: do not export any functions from fsl_pq_mdio.c

None of the functions in fsl_pq_mdio.c are used by any other source file,
so there's no point in exporting them.  Merge the header file into the
source file, make all the functions static, remove any EXPORT_SYMBOL
statements, and delete any #include "fsl_pq_mdio.h" statements.

Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>