uprobes/powerpc: Teach uprobes to ignore gdb breakpoints
Powerpc has many trap variants that could be used by entities like gdb.
Currently, running gdb on a program being traced by uprobes causes an
endless loop since uprobes doesn't understand that the trap was inserted
by some other entity and a SIGTRAP needs to be delivered.
Teach uprobes to ignore breakpoints that do not belong to it.