[MC] Mips linker invokes MagicCode on jumps into native Arm code.

Change-Id: I5604471f7c7b9a5ca2d294f08509e56a2c2fbc33
[MC] Replace generic linker by mlinker, on MIPS only.

Change-Id: Ied9031b144ad955f81135a4e852b9f26abe096ea
[MC] Update linker to support ARM static executables

Change-Id: I16b644286f18f7588970b62e947cab09b264a361
[MC] Set DT_DEBUG dyntab entry if it is writable

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

Change-Id: I4adceed7f8433725518eb3bbf0695869fdaed0e1
Signed-off-by: Chris Dearman <chris@mips.com>