[MIPS] Introduce __pa_symbol()

This patch introduces __pa_symbol() macro which should be used to
calculate the physical address of kernel symbols. It also relies
on RELOC_HIDE() to avoid any compiler's oddities when doing
arithmetics on symbols.
Signed-off-by: NFranck Bui-Huu <fbuihuu@gmail.com>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

include/asm-mips/page.h

@@ -142,6 +142,7 @@ typedef struct { unsigned long pgprot; } pgprot_t;
 #define __pa_page_offset(x)	PAGE_OFFSET
 #endif
 #define __pa(x)			((unsigned long)(x) - __pa_page_offset(x))
+#define __pa_symbol(x)		__pa(RELOC_HIDE((unsigned long)(x),0))
 #define __va(x)			((void *)((unsigned long)(x) + PAGE_OFFSET))
 
 #define pfn_to_kaddr(pfn)	__va((pfn) << PAGE_SHIFT)