crypto: mediatek - don't return garbage err on successful return

In the case where keylen <= bs mtk_sha_setkey returns an uninitialized
return value in err.  Fix this by returning 0 instead of err.

Issue detected by static analysis with cppcheck.

Signed-off-by: Colin Ian King <[email protected]>
Signed-off-by: Herbert Xu <[email protected]>
1 file changed