iwlwifi: add missing blank, unwrap line

The original commit was missing a space between two words due to
uncareful string line wrapping; let the string run beyond the 80 char
limit in order to also make it grep-able [1].

Reported by: jrtc27, Chris Torek (chris.torek gmail.com)
Suggested by: emaste, imp [1]
Sponsored by: The FreeBSD Foundation
Fixes: 87e140a5c6f89 avoid (hard) hang on loading module
MFC after: 3 days
X-MFC with: 87e140a5c6f89eea7ea6320d1ae34566492abfc0
Reviewed by: emaste
Differential Revision: https://reviews.freebsd.org/D48155