[APX EGPR] Map reg/mem constraints in inline asm to non-EGPR constraint.

In inline asm, we do not know if the insn can use EGPR, so disable EGPR
usage by default via mapping the common reg/mem constraint to non-EGPR
constraints.

The full list of mapping goes like

  "g" -> "jrjmi"
  "r" -> "jr"
  "m" -> "jm"
  "<" -> "j<"
  ">" -> "j>"
  "o" -> "jo"
  "V" -> "jV"
  "p" -> "jp"
  "Bm" -> "ja

For memory constraints, we add an option -mapx-inline-asm-use-gpr32
to allow/disallow gpr32 usage in any memory related constraints, as
base_reg_class/index_reg_class cannot aware whether the asm insn
support gpr32 or not.

gcc/ChangeLog:

	* config/i386/i386.cc (map_egpr_constraints): New funciton to
	map common constraints to EGPR prohibited constraints.
	(ix86_md_asm_adjust): Calls map_egpr_constraints.
	* config/i386/i386.opt: Add option mapx-inline-asm-use-gpr32.

gcc/testsuite/ChangeLog:

	* gcc.target/i386/apx-inline-gpr-norex2.c: New test.

Co-authored-by: Hongyu Wang <hongyu.wang@intel.com>
Co-authored-by: Hongtao Liu <hongtao.liu@intel.com>