[MIPS] Set DT_DEBUG dyntab entry if it is writable

This is primarily for MIPS exutables that do not have a
DT_MIPS_RLD_MAP entry.

Change-Id: I4c221d92debcfed961eeee2515123f3fb21ec8e6
Signed-off-by: Chris Dearman <chris@mips.com>

linker/linker_phdr.h

@@ -99,6 +99,7 @@ phdr_table_get_dynamic_section(const Elf32_Phdr* phdr_table,
                                int               phdr_count,
                                Elf32_Addr        load_bias,
                                Elf32_Addr**      dynamic,
-                               size_t*           dynamic_count);
+                               size_t*           dynamic_count,
+                               Elf32_Word*       dynamic_flags);
 
 #endif /* LINKER_PHDR_H */