You need to add this to the file supporting the tegra board you are using. In the current 3.0-rc3 kernel (last tag I have checked out), I see these tegra board files (in arch/arm/mach-tegra):
- board-harmony.c
- board-paz00.c
- board-seaboard.c
- board-trimslice.c
These files configure the static devices for a given tegra board. Your config file then selects which ones are built. Here are the corresponding config options (from arch/arm/mach-tegra/Kconfig):
comment "Tegra board type"
config MACH_HARMONY
bool "Harmony board"
select MACH_HAS_SND_SOC_TEGRA_WM8903
help
Support for nVidia Harmony development platform
config MACH_KAEN
bool "Kaen board"
select MACH_SEABOARD
select MACH_HAS_SND_SOC_TEGRA_WM8903
help
Support for the Kaen version of Seaboard
config MACH_PAZ00
bool "Paz00 board"
help
Support for the Toshiba AC100/Dynabook AZ netbook
config MACH_SEABOARD
bool "Seaboard board"
select MACH_HAS_SND_SOC_TEGRA_WM8903
help
Support for nVidia Seaboard development platform. It will
also be included for some of the derivative boards that
have large similarities with the seaboard design.
config MACH_TRIMSLICE
bool "TrimSlice board"
select TEGRA_PCI
help
Support for CompuLab TrimSlice platform
config MACH_WARIO
bool "Wario board"
select MACH_SEABOARD
help
Support for the Wario version of Seaboard
Your build system (LTIB) certainly defines one of these config macros (CONFIG_MACH_HARMONY for instance). Look at your config file, see which one is enabled, and add the declaration of your i2c device in the corresponding board-xxx.c file.
