bus: imx-weim: fix branch condition evaluates to a garbage value

bus: imx-weim: fix branch condition evaluates to a garbage value

If bus type is other than imx50_weim_devtype and have no child devices,
variable 'ret' in function weim_parse_dt() will not be initialized, but
will be used as branch condition and return value. Fix this by
initializing 'ret' with 0.

This was discovered with help of clang-analyzer, but the situation is
quite possible in real life.

Fixes: 52c47b63412b ("bus: imx-weim: improve error handling upon child probe-failure")
Signed-off-by: Ivan Bornyakov <i.bornyakov@metrotek.ru>
Cc: stable@vger.kernel.org
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>