clk: stm32mp1: fix missing spin_lock_init()

The driver allocates the spinlock but not initialize it.
Use spin_lock_init() on it to initialize it correctly.

Fixes: c392df19 ("clk: stm32mp1: move RCC reset controller into RCC clock driver")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wang Hai <wanghai38@huawei.com>
Link: https://lore.kernel.org/r/20210630015824.2555840-1-wanghai38@huawei.com


Signed-off-by: Stephen Boyd <sboyd@kernel.org>