staging: wfx: use IS_ALIGNED()

It "IS_ALIGNED(ptr, 4)" is more explicit than "ptr & 3".

Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20220113085524.1110708-9-Jerome.Pouiller@silabs.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>