phy: berlin-usb: remove non-necessary header files

We don't need gpio related header files, so remove them.

Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Acked-by: Antoine Tenart <antoine.tenart@free-electrons.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>