x86/entry: Convert Coprocessor error exception to IDTENTRY

Convert #MF to IDTENTRY_ERRORCODE:
  - Implement the C entry point with DEFINE_IDTENTRY
  - Emit the ASM stub with DECLARE_IDTENTRY
  - Remove the ASM idtentry in 64bit
  - Remove the open coded ASM entry code in 32bit
  - Fixup the XEN/PV code
  - Remove the old prototypes
  - Remove the RCU warning as the new entry macro ensures correctness

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200505134905.838823510@linutronix.de

arch/x86/entry/entry_32.S

@@ -1290,13 +1290,6 @@ SYM_FUNC_END(name)
 /* The include is where all of the SMP etc. interrupts come from */
 #include <asm/entry_arch.h>
 
-SYM_CODE_START(coprocessor_error)
-	ASM_CLAC
-	pushl	$0
-	pushl	$do_coprocessor_error
-	jmp	common_exception
-SYM_CODE_END(coprocessor_error)
-
 SYM_CODE_START(simd_coprocessor_error)
 	ASM_CLAC
 	pushl	$0