xarray: use BITS_PER_LONGS()

xarray: use BITS_PER_LONGS()

Patch series "xarray: Clean up xarray.h".

Main portion of this change is to get rid of kernel.h included into other
globally available headers.  This decreases a dependency hell degree.  The
first patch makes it possible to avoid math.h to be included as bitops.h
is implied by bitmap.h.

This patch (of 2):

Use BITS_PER_LONGS() instead of open coded variant.

Link: https://lkml.kernel.org/r/20240423142204.2408923-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>