ARM: tegra: cpu-tegra: sparse type fix

Type fix:
arch/arm/mach-tegra/cpu-tegra.c:144:14: warning: incorrect type in argument 5 (different signedness)
arch/arm/mach-tegra/cpu-tegra.c:144:14:    expected unsigned int *index
arch/arm/mach-tegra/cpu-tegra.c:144:14:    got int *<noident>

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