ARM: tegra: dma: fix buildbreak for !CONFIG_TEGRA_SYSTEM_DMA

There's no need to keep the DMA_REQ_SEL defines inside the ifdef.

Fixes the following build break with CONFIG_TEGRA_SYSTEM_DMA=n:

arch/arm/mach-tegra/devices.c:645: error: 'TEGRA_DMA_REQ_SEL_I2S_1' undeclared here (not in a function)
arch/arm/mach-tegra/devices.c:663: error: 'TEGRA_DMA_REQ_SEL_I2S2_1' undeclared here (not in a function)
arch/arm/mach-tegra/devices.c:663: error: initializer element is not constant
arch/arm/mach-tegra/devices.c:663: error: (near initialization for 'i2s_resource2[1].start')
arch/arm/mach-tegra/devices.c:664: error: initializer element is not constant
arch/arm/mach-tegra/devices.c:664: error: (near initialization for 'i2s_resource2[1].end')

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