ARM: tegra: do not hide dma declarations

The declarations are actually required for the device
definitions, and are still valid even if the dma controller
is disabled:

arch/arm/mach-tegra/devices.c:559:12: error: 'TEGRA_DMA_REQ_SEL_I2S_1' undeclared here (not in a function)
arch/arm/mach-tegra/devices.c:577:12: error: 'TEGRA_DMA_REQ_SEL_I2S2_1' undeclared here (not in a function)

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alan Ott <alan@signal11.us>
Signed-off-by: Stephen Warren <swarren@nvidia.com>