lightnvm: Fix uninitialized return value in nvm_get_chunk_meta()

lightnvm: Fix uninitialized return value in nvm_get_chunk_meta()

[ Upstream commit 55e58c5e78aad9d3246f57e7718cf5ee7adde9e3 ]

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: aff3fb18f957de93 ("lightnvm: move bad block and chunk state logic to core")
Fixes: a294c199455187d1 ("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>
Signed-off-by: Sasha Levin <sashal@kernel.org>