net: phy: Add support for TI PHY init

net: phy: Add support for TI PHY init

ti_phy_init function was allocated to the DP83867 PHY.  This function
name is to generic for a specific PHY.  The function can be moved to a
TI specific file that can register all TI PHYs that are defined in the
defconfig.  The ti_phy_init file will contain all TI PHYs initialization
so that only phy_ti_init can be called from the framework.

In addition to the above the config flag for the DP83867 needs to be changed
in the Kconfig and dependent defconfig files. The config flag that was
used for the DP83867 was also generic in nature so a more specific
config flag for the DP83867 was created.

Acked-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Dan Murphy <dmurphy@ti.com>