ARM: tegra: devices.c should include devices.h

Resolves lots of sparse warnings:

arch/arm/mach-tegra/devices.c:102:24: warning: symbol 'tegra_i2c_device1' was not declared. Should it be static?
arch/arm/mach-tegra/devices.c:112:24: warning: symbol 'tegra_i2c_device2' was not declared. Should it be static?
arch/arm/mach-tegra/devices.c:122:24: warning: symbol 'tegra_i2c_device3' was not declared. Should it be static?
arch/arm/mach-tegra/devices.c:132:24: warning: symbol 'tegra_i2c_device4' was not declared. Should it be static?
[...]

Signed-off-by: Olof Johansson <olof@lixom.net>
Acked-by: Stephen Warren <swarren@nvidia.com>