net: phy: microchip_t1s: remove unnecessary interrupts disabling code

By default, except Reset Complete interrupt in the Interrupt Mask 2
Register all other interrupts are disabled/masked. As Reset Complete
status is already handled, it doesn't make sense to disable it.

Reviewed-by: Ramón Nordin Rodriguez <ramon.nordin.rodriguez@ferroamp.se>
Tested-by: Ramón Nordin Rodriguez <ramon.nordin.rodriguez@ferroamp.se>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Parthiban Veerasooran <Parthiban.Veerasooran@microchip.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>