mm: vmalloc: fix sparc64 warning

This fixes this warning from a sparc64 defconfig build:

In file included from /home/sfr/next/next/include/linux/wait.h:11,
                 from /home/sfr/next/next/include/linux/swait.h:8,
                 from /home/sfr/next/next/include/linux/completion.h:12,
                 from /home/sfr/next/next/include/linux/mm_types.h:14,
                 from /home/sfr/next/next/include/linux/uio.h:10,
                 from /home/sfr/next/next/include/linux/vmalloc.h:12,
                 from /home/sfr/next/next/include/asm-generic/io.h:994,
                 from /home/sfr/next/next/arch/sparc/include/asm/io.h:22,
                 from /home/sfr/next/next/arch/sparc/vdso/vclock_gettime.c:18:
/home/sfr/next/next/arch/sparc/include/asm/current.h:18:30: warning: call-clobbered register used for global register variable
   18 | register struct task_struct *current asm("g4");
      |                              ^~~~~~~

Fixes: 4e29dd9 ("mm: vmalloc: convert vread() to vread_iter()")
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

include/linux/vmalloc.h

@@ -9,12 +9,12 @@
 #include <asm/page.h>		/* pgprot_t */
 #include <linux/rbtree.h>
 #include <linux/overflow.h>
-#include <linux/uio.h>
 
 #include <asm/vmalloc.h>
 
 struct vm_area_struct;		/* vma defining user mapping in mm_types.h */
 struct notifier_block;		/* in notifier.h */
+struct iov_iter;		/* in uio.h */
 
 /* bits in flags of vmalloc's vm_struct below */
 #define VM_IOREMAP		0x00000001	/* ioremap() and friends */

mm/vmalloc.c

@@ -40,6 +40,7 @@
 #include <linux/hugetlb.h>
 #include <linux/sched/mm.h>
 #include <linux/rwsem.h>
+#include <linux/uio.h>
 #include <asm/tlbflush.h>
 #include <asm/shmparam.h>