iio: adc: ad7280a: Extract chan->address bit fields into named local variables

iio: adc: ad7280a: Extract chan->address bit fields into named local variables

Extract the upper and lower bytes of chan->address into named local
variables devaddr and ch across ad7280_read_raw(),
ad7280_show_balance_timer() and ad7280_store_balance_timer() to improve
readability and avoid inline bit manipulation in function calls.

Suggested-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Lucas Ivars Cadima Ciziks <lucas@ciziks.com>
Co-developed-by: Matheus Giarola <matheusgiarola@usp.br>
Signed-off-by: Matheus Giarola <matheusgiarola@usp.br>
Co-developed-by: Felipe Ribeiro de Souza <felipers@usp.br>
Signed-off-by: Felipe Ribeiro de Souza <felipers@usp.br>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>