ARM: tegra: MASK_BITS_ no longer needs specific values

Since all code that sets or interprets MASK_BITS_* now uses the enums
to define/compare the values, there is no need for MASK_BITS_* to have
a specific integer value. In fact, having a specific integer value may
encourage people to hard-code those values, or interpret the values in
incorrect ways.

As such, remove the logic that assigns a specific value to the enum
values in order to make it completely clear that it's just an enum, not
something that directly represents some integer value.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Tested-by: Thierry Reding <treding@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>