clk: tegra: Drop !provider check in tegra210_clk_emc_set_rate()

clk: tegra: Drop !provider check in tegra210_clk_emc_set_rate()

The provider variable is already dereferenced earlier in this function.
Drop the check for NULL as it is impossible.

Found with smatch

drivers/clk/tegra/clk-tegra210-emc.c:131 tegra210_clk_emc_set_rate() warn: variable dereferenced before check 'provider' (see line 124)

Cc: Joseph Lo <josephl@nvidia.com>
Cc: Thierry Reding <treding@nvidia.com>
Fixes: 0ac65fc946d3 ("clk: tegra: Implement Tegra210 EMC clock")
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lore.kernel.org/r/20200922191641.2305144-1-sboyd@kernel.org
Acked-by: Thierry Reding <treding@nvidia.com>