clk: tegra: clk-tegra30: Remove unused variable 'reg'

Fixes the following W=1 kernel build warning(s):

 drivers/clk/tegra/clk-tegra30.c: In function ‘tegra30_enable_cpu_clock’:
 drivers/clk/tegra/clk-tegra30.c:1107:15: warning: variable ‘reg’ set but not used [-Wunused-but-set-variable]

Cc: Peter De Schrijver <pdeschrijver@nvidia.com>
Cc: Prashant Gaikwad <pgaikwad@nvidia.com>
Cc: Michael Turquette <mturquette@baylibre.com>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: linux-clk@vger.kernel.org
Cc: linux-tegra@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20210126124540.3320214-8-lee.jones@linaro.org


Signed-off-by: Stephen Boyd <sboyd@kernel.org>