csky: Add support for perf registers sampling

This patch implements the perf registers sampling and validation API
for csky arch. The valid registers and their register ID are defined in
perf_regs.h. Perf tool can backtrace in userspace with unwind library
and the registers/user stack dump support.

Signed-off-by: Mao Han <han_mao@c-sky.com>
Signed-off-by: Guo Ren <ren_guo@c-sky.com>
diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig
index c4974cf..8e45c7a 100644
--- a/arch/csky/Kconfig
+++ b/arch/csky/Kconfig
@@ -38,6 +38,8 @@
 	select HAVE_KERNEL_LZO
 	select HAVE_KERNEL_LZMA
 	select HAVE_PERF_EVENTS
+	select HAVE_PERF_REGS
+	select HAVE_PERF_USER_STACK_DUMP
 	select HAVE_DMA_API_DEBUG
 	select HAVE_DMA_CONTIGUOUS
 	select HAVE_SYSCALL_TRACEPOINTS