Fix link errors when CONFIG_FSL_USB2_OTG is enabled and USB_OTG_FSM is
set to module then the following link error occurs.

aarch64-linux-gnu-ld: drivers/usb/phy/phy-fsl-usb.o: in function `fsl_otg_ioctl':
drivers/usb/phy/phy-fsl-usb.c:1083: undefined reference to `otg_statemachine'
aarch64-linux-gnu-ld: drivers/usb/phy/phy-fsl-usb.c:1083:(.text+0x574): relocation truncated to fit: R_AARCH64_CALL26 against undefined symbol `otg_statemachine'
aarch64-linux-gnu-ld: drivers/usb/phy/phy-fsl-usb.o: in function `fsl_otg_start_srp':
drivers/usb/phy/phy-fsl-usb.c:674: undefined reference to `otg_statemachine'
aarch64-linux-gnu-ld: drivers/usb/phy/phy-fsl-usb.c:674:(.text+0x61c): relocation truncated to fit: R_AARCH64_CALL26 against undefined symbol `otg_statemachine'
aarch64-linux-gnu-ld: drivers/usb/phy/phy-fsl-usb.o: in function `fsl_otg_set_host':
drivers/usb/phy/phy-fsl-usb.c:593: undefined reference to `otg_statemachine'
aarch64-linux-gnu-ld: drivers/usb/phy/phy-fsl-usb.c:593:(.text+0x7a4): relocation truncated to fit: R_AARCH64_CALL26 against undefined symbol `otg_statemachine'
aarch64-linux-gnu-ld: drivers/usb/phy/phy-fsl-usb.o: in function `fsl_otg_start_hnp':
drivers/usb/phy/phy-fsl-usb.c:695: undefined reference to `otg_statemachine'
aarch64-linux-gnu-ld: drivers/usb/phy/phy-fsl-usb.c:695:(.text+0x858): relocation truncated to fit: R_AARCH64_CALL26 against undefined symbol `otg_statemachine'
aarch64-linux-gnu-ld: drivers/usb/phy/phy-fsl-usb.o: in function `a_wait_enum':
drivers/usb/phy/phy-fsl-usb.c:274: undefined reference to `otg_statemachine'
aarch64-linux-gnu-ld: drivers/usb/phy/phy-fsl-usb.c:274:(.text+0x16f0): relocation truncated to fit: R_AARCH64_CALL26 against undefined symbol `otg_statemachine'
aarch64-linux-gnu-ld: drivers/usb/phy/phy-fsl-usb.o:drivers/usb/phy/phy-fsl-usb.c:619: more undefined references to `otg_statemachine' follow
aarch64-linux-gnu-ld: drivers/usb/phy/phy-fsl-usb.o: in function `fsl_otg_set_peripheral':
drivers/usb/phy/phy-fsl-usb.c:619:(.text+0x1fa0): relocation truncated to fit: R_AARCH64_CALL26 against undefined symbol `otg_statemachine'
make[1]: *** [Makefile:1020: vmlinux] Error 1
make[1]: Target 'Image' not remade because of errors.
make: *** [Makefile:152: sub-make] Error 2
make: Target 'Image' not remade because of errors.

Rework so that FSL_USB2_OTG depends on that the USB_OTG_FSM is builtin.
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>