sparc: remove unnecessary includes

linux/highmem.h has not been needed for the pte_offset_map => kmap_atomic
use in sparc for some time (~2002)

Remove this include.
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christian König <christian.koenig@amd.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chris Zankel <chris@zankel.net>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Helge Deller <deller@gmx.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200507150004.1423069-15-ira.weiny@intel.comSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/sparc/mm/io-unit.c

@@ -10,7 +10,6 @@
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/mm.h>
-#include <linux/highmem.h>	/* pte_offset_map => kmap_atomic */
 #include <linux/bitops.h>
 #include <linux/dma-mapping.h>
 #include <linux/of.h>

arch/sparc/mm/iommu.c

@@ -12,7 +12,6 @@
 #include <linux/init.h>
 #include <linux/mm.h>
 #include <linux/slab.h>
-#include <linux/highmem.h>	/* pte_offset_map => kmap_atomic */
 #include <linux/dma-mapping.h>
 #include <linux/of.h>
 #include <linux/of_device.h>