staging: iio: resolver: Remove & on function name to align with other IIO drivers.

Remove & from function pointers to conform to the style found in the wider
subsystem.  Done using the following semantic patch

// <smpl>
@r@
identifier f;
@@

f(...) { ... }
@@
identifier r.f;
@@

- &f
+ f
// </smpl>

Signed-off-by: simran singhal <singhalsimran0@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>