tools: iio: Remove unnecessary braces

Single statement blocks don’t need braces.
Found with checkpatch.pl.

Signed-off-by: Cristina Opriceana <cristina.opriceana@gmail.com>
Acked-by: Hartmut Knaack <knaack.h@gmx.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>