This is a workaround for linker error when compiling with -O0

  `.text._Z9safe_loadIcEbPKT_RS0_' referenced in section `.text.fixup'
  of core/mmu.o: defined in discarded section
  `.text._Z9safe_loadIcEbPKT_RS0_[_Z9safe_loadIcEbPKT_RS0_]' of
  core/mmu.o

The safe_load() template is used in both runtime.cc and core/mmu.cc
but the linker keeps it only in one section discarding the other.

Signed-off-by: Tomasz Grabiec <tgrabiec@cloudius-systems.com>