csky: Fix perf record in kernel/user space

csky_pmu_event_init is called several times during the perf record
initialzation. After configure the event counter in either kernel
space or user space, csky_pmu_event_init is called twice with no
attr specified. Configuration will be overwritten with sampling in
both kernel space and user space. --all-kernel/--all-user is
useless without this patch applied.

Signed-off-by: Mao Han <han_mao@c-sky.com>
Signed-off-by: Guo Ren <guoren@kernel.org>