memory: tegra: Make terga20_mc_reset_ops static

Fix sparse warning:

drivers/memory/tegra/tegra20.c:277:33: warning:
 symbol 'terga20_mc_reset_ops' was not declared. Should it be static?
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Yue Haibing <yuehaibing@huawei.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/memory/tegra/tegra20.c

@@ -274,7 +274,7 @@ static int terga20_mc_unblock_dma(struct tegra_mc *mc,
 	return 0;
 }
 
-const struct tegra_mc_reset_ops terga20_mc_reset_ops = {
+static const struct tegra_mc_reset_ops terga20_mc_reset_ops = {
 	.hotreset_assert = terga20_mc_hotreset_assert,
 	.hotreset_deassert = terga20_mc_hotreset_deassert,
 	.block_dma = terga20_mc_block_dma,