gcc-9: don't warn about uninitialized variable

I'm not sure what made gcc warn about this code now.  The 'ret' variable
does end up initialized in all cases, but it's definitely not obvious,
so the compiler is quite reasonable to warn about this.

So just add initialization to make it all much more obvious both to
compilers and to humans.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>