target-alpha: Raise IOV from CVTQL

target-alpha: Raise IOV from CVTQL

Even if an exception isn't taken, the status flags need updating
and the result should be written to the destination.  Move the body
of cvtql out of line, since we now always need a call.

Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Richard Henderson <rth@twiddle.net>