net: phy: Export gen10g_* functions

In order to remove a fair amount of duplication in the different 10G PHY
drivers, export all gen10g_* functions to be able to make use of those.
While we are at it, rename gen10g_soft_reset() to gen10g_no_soft_reset()
to illustrate what it does.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>