x86/mm: Unexport set_memory_x() and set_memory_nx()

No module currently messed with clearing or setting the execute
permission of kernel memory, and none really should.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190826075558.8125-2-hch@lst.deSigned-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/mm/pageattr.c

@@ -1977,7 +1977,6 @@ int set_memory_x(unsigned long addr, int numpages)
 
 	return change_page_attr_clear(&addr, numpages, __pgprot(_PAGE_NX), 0);
 }
-EXPORT_SYMBOL(set_memory_x);
 
 int set_memory_nx(unsigned long addr, int numpages)
 {
@@ -1986,7 +1985,6 @@ int set_memory_nx(unsigned long addr, int numpages)
 
 	return change_page_attr_set(&addr, numpages, __pgprot(_PAGE_NX), 0);
 }
-EXPORT_SYMBOL(set_memory_nx);
 
 int set_memory_ro(unsigned long addr, int numpages)
 {