usb: phy: samsung: Pass set_isolation callback through driver data

This patch extends driver data structure with set_isolation callback,
which allows to remove the need for checking for SoC type in a switch
statement.

Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>