iio: dht11: whitespace changes to make checkpatch.pl --strict happy

* add spaces around binary operators in cases where it reduces readability
* align multiline statements around opening parenthesis

Reported-by: Hartmut Knaack <knaack.h@gmx.de>
	in Message-ID: <55919E72.3010807@gmx.de>

Signed-off-by: Harald Geyer <harald@ccbib.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>