m68k: sun3: Fix context restore in flush_tlb_range()

When building with W=1:

    In file included from arch/m68k/kernel/traps.c:42:
    arch/m68k/include/asm/tlbflush.h: In function ‘flush_tlb_range’:
    arch/m68k/include/asm/tlbflush.h:191:28: warning: variable ‘oldctx’ set but not used [-Wunused-but-set-variable]
      191 |         unsigned char seg, oldctx;
	  |                            ^~~~~~

Indeed, the old context is saved, but never restored.  Fix this by
adding the missing call to sun3_put_context().
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/ea859b7850e061e0f7fb3fca64d9f8e6d1c0d2ad.1694613528.git.geert@linux-m68k.org

arch/m68k/include/asm/tlbflush.h

@@ -208,6 +208,7 @@ static inline void flush_tlb_range (struct vm_area_struct *vma,
 	next:
 		start += SUN3_PMEG_SIZE;
 	}
+	sun3_put_context(oldctx);
 }
 
 static inline void flush_tlb_kernel_range(unsigned long start, unsigned long end)