block: mtip32xx: set error code on failure

block: mtip32xx: set error code on failure

Fix bug https://bugzilla.kernel.org/show_bug.cgi?id=188531. In function
mtip_block_initialize(), variable rv takes the return value, and its
value should be negative on errors. rv is initialized as 0 and is not
reset when the call to ida_pre_get() fails. So 0 may be returned.
The return value 0 indicates that there is no error, which may be
inconsistent with the execution status. This patch fixes the bug by
explicitly assigning -ENOMEM to rv on the branch that ida_pre_get()
fails.

Signed-off-by: Pan Bian <bianpan2016@163.com>
Signed-off-by: Jens Axboe <axboe@fb.com>