avb: Fix error when partition not found

part_get_info_by_name will return -1 on error, and >0 on success.

Signed-off-by: schspa <schspa@gmail.com>
Cc: Igor Opaniuk <igor.opaniuk@gmail.com>
Reviewed-by: Igor Opaniuk <igor.opaniuk@gmail.com>
1 file changed