regmap: spi-avmm: Use swabXX_array() helpers

Since we have a few helpers to swab elements of a given size in an array
use them instead of open coded variants.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20220831212744.56435-3-andriy.shevchenko@linux.intel.com


Signed-off-by: Mark Brown <broonie@kernel.org>