ARM: mmp: Make some symbols static

These symbols pxa168_usb_phy_resources, pxa168_u2o_resources,
pxa168_u2oehci_resources and pxa168_u2ootg_resources are not used
outside of arch/arm/mach-mmp/devices.c, so mark them static.

Fixes the following sparse warning:

arch/arm/mach-mmp/devices.c:241:17: warning: symbol 'pxa168_usb_phy_resources' was not declared. Should it be static?
arch/arm/mach-mmp/devices.c:262:17: warning: symbol 'pxa168_u2o_resources' was not declared. Should it be static?
arch/arm/mach-mmp/devices.c:297:17: warning: symbol 'pxa168_u2oehci_resources' was not declared. Should it be static?
arch/arm/mach-mmp/devices.c:324:17: warning: symbol 'pxa168_u2ootg_resources' was not declared. Should it be static?

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Chen Lifu <chenlifu@huawei.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>