lightnvm: Fix uninitialized return value in nvm_get_chunk_meta()

With gcc 4.1:

    drivers/lightnvm/core.c: In function ‘nvm_get_bb_meta’:
    drivers/lightnvm/core.c:977: warning: ‘ret’ may be used uninitialized in this function

and

    drivers/nvme/host/lightnvm.c: In function ‘nvme_nvm_get_chk_meta’:
    drivers/nvme/host/lightnvm.c:580: warning: ‘ret’ may be used uninitialized in this function

Indeed, if (for the former) the number of channels or LUNs is zero, or
(for both) the passed number of chunks is zero, ret will be returned
uninitialized.

Fix this by preinitializing ret to zero.

Fixes: aff3fb18 ("lightnvm: move bad block and chunk state logic to core")
Fixes: a294c199 ("lightnvm: implement get log report chunk helpers")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Matias Bjørling <mb@lightnvm.io>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/lightnvm/core.c

@@ -974,7 +974,7 @@ static int nvm_get_bb_meta(struct nvm_dev *dev, sector_t slba,
 	struct ppa_addr ppa;
 	u8 *blks;
 	int ch, lun, nr_blks;
-	int ret;
+	int ret = 0;
 
 	ppa.ppa = slba;
 	ppa = dev_to_generic_addr(dev, ppa);

drivers/nvme/host/lightnvm.c

@@ -577,7 +577,8 @@ static int nvme_nvm_get_chk_meta(struct nvm_dev *ndev,
 	struct ppa_addr ppa;
 	size_t left = nchks * sizeof(struct nvme_nvm_chk_meta);
 	size_t log_pos, offset, len;
-	int ret, i, max_len;
+	int i, max_len;
+	int ret = 0;
 
 	/*
 	 * limit requests to maximum 256K to avoid issuing arbitrary large