ASoC: tegra20-ac97: Remove unused variable

With the conversion to devm_ioremap_resource() the memregion variable is
no longer used so it can be dropped.
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

sound/soc/tegra/tegra20_ac97.c

@@ -312,7 +312,7 @@ static const struct regmap_config tegra20_ac97_regmap_config = {
 static int tegra20_ac97_platform_probe(struct platform_device *pdev)
 {
 	struct tegra20_ac97 *ac97;
-	struct resource *mem, *memregion;
+	struct resource *mem;
 	u32 of_dma[2];
 	void __iomem *regs;
 	int ret = 0;