ARM: mmp: fix pxa168_device_usb_phy use on aspenite

This one ended up in the wrong header file, causing a build failure
on at least one platform:

arch/arm/mach-mmp/aspenite.c: In function 'common_init':
arch/arm/mach-mmp/aspenite.c:260:28: error: 'pxa168_device_usb_phy' undeclared (first use in this function); did you mean 'pxa168_device_ssp5'?

We can just include both the pxa168.h and pxa910.h headers to make
that work, which gets us to the next failure:

arch/arm/mach-mmp/aspenite.o: In function `common_init':
aspenite.c:(.init.text+0x1c0): undefined reference to `pxa168_device_usb_phy'

This is solved by using the matching ifdef check around the
USB device registration, enabling them only when either USB
host or gadget mode are enabled.

Fixes: a225daf7 ("ARM: mmp: add a pxa-usb-phy device")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Olof Johansson <olof@lixom.net>