ARM: add uprobes support

Using Rabin Vincent's ARM uprobes patches as a base, enable uprobes
support on ARM.

Caveats:

 - Thumb is not supported

Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: David A. Long <dave.long@linaro.org>

diff --cc arch/arm/Kconfig
Simple merge

diff --cc arch/arm/include/asm/ptrace.h
Simple merge

diff --cc arch/arm/include/asm/thread_info.h
Simple merge

diff --cc arch/arm/include/asm/uprobes.h
Simple merge

diff --cc arch/arm/kernel/Makefile
Simple merge

diff --cc arch/arm/kernel/signal.c
Simple merge

diff --cc arch/arm/kernel/uprobes-arm.c
Simple merge

diff --cc arch/arm/kernel/uprobes.c
Simple merge

diff --cc arch/arm/kernel/uprobes.h
Simple merge