Fixes a regression from e9c3c494 where
although we use the last report length, it was only initialized after
the first corresponding report was received. Calling HidD_GetInputReport
before that could cause a buffer overlow and report invalid data.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=52068Signed-off-by: Rémi Bernon <rbernon@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>