nvmem: mtk-efuse: Remove EFUSE register write support

This patch is to remove function "mtk_reg_write" since
Mediatek EFUSE hardware only supports read functionality
for NVMEM consumers.

Fixes: ba360fd0 ("nvmem: mtk-efuse: remove nvmem regmap dependency")
Acked-by: Andrew-CT Chen <andrew-ct.chen@mediatek.com>
Signed-off-by: Chih-En Hsu <chih-en.hsu@mediatek.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200917134437.16637-2-srinivas.kandagatla@linaro.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/nvmem/mtk-efuse.c

@@ -28,19 +28,6 @@ static int mtk_reg_read(void *context,
 	return 0;
 }
 
-static int mtk_reg_write(void *context,
-			 unsigned int reg, void *_val, size_t bytes)
-{
-	struct mtk_efuse_priv *priv = context;
-	u32 *val = _val;
-	int i = 0, words = bytes / 4;
-
-	while (words--)
-		writel(*val++, priv->base + reg + (i++ * 4));
-
-	return 0;
-}
-
 static int mtk_efuse_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -61,7 +48,6 @@ static int mtk_efuse_probe(struct platform_device *pdev)
 	econfig.stride = 4;
 	econfig.word_size = 4;
 	econfig.reg_read = mtk_reg_read;
-	econfig.reg_write = mtk_reg_write;
 	econfig.size = resource_size(res);
 	econfig.priv = priv;
 	econfig.dev = dev;