mtd: nand: drop EXPORT_SYMBOL_GPL for nanddev_erase()

This function is only used within this module, so it is no longer
necessary to use EXPORT_SYMBOL_GPL().

This patch parallels the work done in the following patch:
https://lore.kernel.org/linux-mtd/20221018170205.1733958-1-dario.binacchi@amarulasolutions.com

Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
Reviewed-By: Michael Trimarchi <michael@amarulasolutions.com>
Link: https://lore.kernel.org/all/20221108090719.3631621-1-dario.binacchi@amarulasolutions.com
diff --git a/drivers/mtd/nand/core.c b/drivers/mtd/nand/core.c
index 99c2967..4b9dd6a 100644
--- a/drivers/mtd/nand/core.c
+++ b/drivers/mtd/nand/core.c
@@ -129,7 +129,7 @@
  *
  * Return: 0 in case of success, a negative error code otherwise.
  */
-int nanddev_erase(struct nand_device *nand, const struct nand_pos *pos)
+static int nanddev_erase(struct nand_device *nand, const struct nand_pos *pos)
 {
 	unsigned int entry;
 
@@ -147,7 +147,6 @@
 
 	return nand->ops->erase(nand, pos);
 }
-EXPORT_SYMBOL_GPL(nanddev_erase);
 
 /**
  * nanddev_mtd_erase() - Generic mtd->_erase() implementation for NAND devices
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index 7774c17..aeb38de 100644
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -691,7 +691,6 @@
 
 bool nanddev_isbad(struct nand_device *nand, const struct nand_pos *pos);
 bool nanddev_isreserved(struct nand_device *nand, const struct nand_pos *pos);
-int nanddev_erase(struct nand_device *nand, const struct nand_pos *pos);
 int nanddev_markbad(struct nand_device *nand, const struct nand_pos *pos);
 
 /* BBT related functions */