clk: stm32: rcc_reset: 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: 637cee5f

 ("clk: stm32: Introduce STM32MP13 RCC drivers (Reset Clock Controller)")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Link: https://lore.kernel.org/r/20220608021154.990347-1-weiyongjun1@huawei.com
Tested-by: Gabriel Fernandez <gabriel.fernandez@foss.st.com>
Reviewed-by: Gabriel Fernandez <gabriel.fernandez@foss.st.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>