net: fsl_mdio: Fix warnings for __iomem pointers

net: fsl_mdio: Fix warnings for __iomem pointers

Add the __iomem address space marker for the tsec pointers
to struct tsec_mii_mng memory mapped register regions.
This solves the sparse warnings for mixig normal pointers with
__iomem pointers for tsec. E.g.:

fsl_mdio.c:34:19: warning: incorrect type in argument 1 (different
address spaces)
fsl_mdio.c:34:19:    expected unsigned int volatile [noderef]
<asn:2>*addr
fsl_mdio.c:34:19:    got unsigned int *<noident>
[...]

tsec.c:91:35: warning: incorrect type in argument 1 (different address
spaces)
tsec.c:91:35:    expected struct tsec_mii_mng *phyregs
tsec.c:91:35:    got struct tsec_mii_mng [noderef] <asn:2>*phyregs_sgmii
[...]

tsec.c:680:19: warning: incorrect type in assignment (different address
spaces)
tsec.c:680:19:    expected struct tsec_mii_mng *regs
tsec.c:680:19:    got struct tsec_mii_mng [noderef] <asn:2>*<noident>
[...]

Signed-off-by: Claudiu Manoil <claudiu.manoil@freescale.com>