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 <[e-mail]>
Acked-by: Jon Hunter <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Krzysztof Kozlowski <[e-mail]>

drivers/memory/tegra/tegra186.c

···
 	return 0;
 }
 
+#if IS_ENABLED(CONFIG_IOMMU_API)
 static void tegra186_mc_client_sid_override(struct tegra_mc *mc,
 					    const struct tegra_mc_client *client,
 					    unsigned int sid)
···
 		writel(sid, mc->regs + client->regs.sid.override);
 	}
 }
+#endif
 
 static int tegra186_mc_probe_device(struct tegra_mc *mc, struct device *dev)
 {