Revert "parisc: Export flush_cache_page() (needed by lustre)"

This reverts commit 320c90be.

Christoph Hellwig <hch@infradead.org> commented:
This one shouldn't go in - Geert sent it a bit prematurely, as Lustre
shouldn't use it just to reimplement core VM functionality (which it
shouldn't use either, but that's a separate story).
Signed-off-by: Helge Deller <deller@gmx.de>

arch/parisc/kernel/cache.c

@@ -602,7 +602,6 @@ flush_cache_page(struct vm_area_struct *vma, unsigned long vmaddr, unsigned long
 		__flush_cache_page(vma, vmaddr, PFN_PHYS(pfn));
 	}
 }
-EXPORT_SYMBOL_GPL(flush_cache_page);
 
 #ifdef CONFIG_PARISC_TMPALIAS