remoteproc: fix missing fault indication in error-path

If rproc_find_rsc_table() fails, rproc_fw_boot() must set
return-value before jumping to clean_up label. Otherwise no
error value is returned.

Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Cc: stable@vger.kernel.org