ARM: tegra: clock: Export clk registration

ARM: tegra: clock: Export clk registration

The GPU driver should be buildable as a module, however, it
needs to register the GPCPLL into the clock framework. This
patch exports the tegra_clk_register_export_ops() symbol to allow
the GPU driver register the internal clock.

Bug 1476801

Change-Id: Ic6514a13cc54b51e24c8989b386e0c744831bf20
Signed-off-by: Arto Merilainen <amerilainen@nvidia.com>
Reviewed-on: http://git-master/r/387606
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>