[nrf fromtree] mgmt/mcumgr: Replace use of flash_area_erase with flash_area_flatten

The commit replaces flash_area_erase with flash_area_flatten.
The function is used in to places:
 1) in image management commands IMG_MGMT_ID_UPLOAD
    and IMG_MGMT_ID_ERASE: to erase an image in secondary slot
    or to scramble trailer part of image, which could be misunderstood
    by MCUboot as valid image operation request;
 2) in command ZEPHYR_MGMT_GRP_BASIC_CMD_ERASE_STORAGE to
    erase/scramble data partition.

Signed-off-by: Dominik Ermel <[email protected]>
(cherry picked from commit bce06a6)

Author: de-nordic

subsys/mgmt/mcumgr/grp/img_mgmt/src/zephyr_img_mgmt.c

@@ -294,7 +294,7 @@ int img_mgmt_erase_slot(int slot)
 	rc = img_mgmt_flash_check_empty_inner(fa);
 
 	if (rc == 0) {
-		rc = flash_area_erase(fa, 0, fa->fa_size);
+		rc = flash_area_flatten(fa, 0, fa->fa_size);
 
 		if (rc != 0) {
 			LOG_ERR("Failed to erase flash area: %d", rc);
@@ -473,7 +473,7 @@ int img_mgmt_erase_image_data(unsigned int off, unsigned int num_bytes)
 
 	size_t erase_size = page.start_offset + page.size - fa->fa_off;
 
-	rc = flash_area_erase(fa, 0, erase_size);
+	rc = flash_area_flatten(fa, 0, erase_size);
 
 	if (rc != 0) {
 		LOG_ERR("image slot erase of 0x%zx bytes failed (err %d)", erase_size,
@@ -498,7 +498,7 @@ int img_mgmt_erase_image_data(unsigned int off, unsigned int num_bytes)
 		off = page.start_offset - fa->fa_off;
 		erase_size = fa->fa_size - off;
 
-		rc = flash_area_erase(fa, off, erase_size);
+		rc = flash_area_flatten(fa, off, erase_size);
 		if (rc != 0) {
 			LOG_ERR("image slot trailer erase of 0x%zx bytes failed (err %d)",
 					erase_size, rc);

subsys/mgmt/mcumgr/grp/zephyr_basic/src/basic_mgmt.c

@@ -31,7 +31,7 @@ static int storage_erase(void)
 			LOG_ERR("Failed to get flash area device");
 			rc = ZEPHYRBASIC_MGMT_ERR_FLASH_CONFIG_QUERY_FAIL;
 		} else {
-			rc = flash_area_erase(fa, 0, fa->fa_size);
+			rc = flash_area_flatten(fa, 0, fa->fa_size);
 
 			if (rc < 0) {
 				LOG_ERR("Failed to erase flash area");