Fix broken GDB build after adding Bound table support for i386.

Fix broken GDB build after adding Bound table support for i386.

Types used for some variables could not be used for 32 bits, causing a
compilation failure.
This patch adds a cast to force a quite compilation, but at the same
time it bails out in the case that the cast performed is not safe, i.e.
in the case where the debuggee is 64bit and debugger is 32bit.

Documentation was also affected, once a different version of texinfo the
docs could not be build.

2015-06-10  Walfred Tedeschi  <walfred.tedeschi@intel.com>

	* i386-tdep.c (i386_mpx_get_bt_entry): Add a cast for mpx_bd_mask
	and bt_mask to CORE_ADDR.

doc:
	* gdb.textinfo (i386): Fix "@end table" end and "@table" placement.