mm: hugetlb_vmemmap: include missing linux/moduleparam.h

The kernel test robot reported build failures with a 'randconfig' on s390:
>> mm/hugetlb_vmemmap.c:421:11: error: a function declaration without a
prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
core_param(hugetlb_free_vmemmap, vmemmap_optimize_enabled, bool, 0);
^

Link: https://lore.kernel.org/linux-mm/[e-mail]/
Link: https://lkml.kernel.org/r/[e-mail]
Fixes: 30152245c63b ("mm: hugetlb_vmemmap: replace early_param() with core_param()")
Signed-off-by: Vasily Gorbik <[e-mail]>
Reported-by: kernel test robot <[e-mail]>
Reviewed-by: Muchun Song <[e-mail]>
Cc: Gerald Schaefer <[e-mail]>
Cc: Mike Kravetz <[e-mail]>
Cc: <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

mm/hugetlb_vmemmap.c

···
 #define pr_fmt(fmt)	"HugeTLB: " fmt
 
 #include <linux/pgtable.h>
+#include <linux/moduleparam.h>
 #include <linux/bootmem_info.h>
 #include <asm/pgalloc.h>
 #include <asm/tlbflush.h>