powerpc/kprobes: Rename opcode_t in probes.h to ppc_opcode_t

powerpc/kprobes: Rename opcode_t in probes.h to ppc_opcode_t

commit: 025dbe29a36fb8bb31d3bc25e7cc95473d5f19fe
[24/29] powerpc: Uprobes port to powerpc

Caused a clash with the fore200e driver:

In file included from drivers/atm/fore200e.c:70:0:
drivers/atm/fore200e.h:263:3: error: redefinition of typedef 'opcode_t' with different type
arch/powerpc/include/asm/probes.h:25:13: note: previous declaration of 'opcode_t' was here

Fix the namespace clash by making opcode_t in probes.h to ppc_opcode_t.

Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>