usb: musb: remove dummy driver musb_am335x.c

Since commit 0782e857 ("ARM: dts: Probe am335x musb with ti-sysc"),
the dummy driver musb_am335x.c is no longer needed, let's drop it.

Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Bin Liu <b-liu@ti.com>
Link: https://lore.kernel.org/r/20200115132547.364-26-b-liu@ti.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>