Remove pagex pseudo page fault code.  It does not work together with the
system call speedup that makes the complete system call path enabled for
interrupts.  To make pagex and the syscall speedup code work together we would
have to add code to the program check handler to do a critical section cleanup
like the asynchronous interrupt code.  This would make program checks slower.
Not what we want.

Newer versions of z/VM have the improved pfault pseudo page fault interface.
This replaces the old pagex interface and does not have the problem.  So its
better to just rip out the pagex code.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>