memory: tegra: fix unused-function warning

memory: tegra: fix unused-function warning

The tegra186_mc_client_sid_override() is only called from
an #ifdef block:

drivers/memory/tegra/tegra186.c:74:13: error: 'tegra186_mc_client_sid_override' defined but not used [-Werror=unused-function]
   74 | static void tegra186_mc_client_sid_override(struct tegra_mc *mc,
      |             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Add another #ifdef around the called function.

Fixes: 393d66fd2cac ("memory: tegra: Implement SID override programming")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Link: https://lore.kernel.org/r/20210722090748.1157470-1-arnd@kernel.org
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>