net: phy: mxl-gpy: Remove interrupt mask clearing from config_init

When the system resumes from sleep, the phy_init_hw() function invokes
config_init(), which clears all interrupt masks and causes wake events to be
lost in subsequent wake sequences. Remove interrupt mask clearing from
config_init() and preserve relevant masks in config_intr().

Fixes: 7d901a1e

 ("net: phy: add Maxlinear GPY115/21x/24x driver")
Reviewed-by: Wojciech Drewek <wojciech.drewek@intel.com>
Signed-off-by: Raju Lakkaraju <Raju.Lakkaraju@microchip.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>