ia64: mca_drv: fix incorrect array size calculation

gcc points out a mistake in the mca driver that goes back to before the
git history:

arch/ia64/kernel/mca_drv.c: In function 'init_record_index_pools':
arch/ia64/kernel/mca_drv.c:346:54: error: expression does not compute the number of elements in this array; element typ
e is 'int', not 'size_t' {aka 'long unsigned int'} [-Werror=sizeof-array-div]
  346 |         for (i = 1; i < sizeof sal_log_sect_min_sizes/sizeof(size_t); i++)
      |                                                      ^

This is the same as sizeof(size_t), which is two shorter than the actual
array.  Use the ARRAY_SIZE() macro to get the correct calculation instead.

Link: https://lkml.kernel.org/r/20210514214123.875971-1-arnd@kernel.org


Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>