[MIPS] pg-r4k.c: Dump the generated code

Dump the generated code for clear/copy page calls like it is done for TLB 
fault handlers.  Useful for debugging.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>