drivers: clk: st: Fix flexgen lock init

While proving lock, the following warning happens
and it is fixed after initializing lock in the setup
function

INFO: trying to register non-static key.
the code is fine but needs lockdep annotation.
turning off the locking correctness validator.
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.10.27-02861-g39df285-dirty #33
[<c00154ac>] (unwind_backtrace+0x0/0xf4) from [<c0011b50>] (show_stack+0x10/0x14)
[<c0011b50>] (show_stack+0x10/0x14) from [<c00689ac>] (__lock_acquire+0x900/0xb14)
[<c00689ac>] (__lock_acquire+0x900/0xb14) from [<c0069394>] (lock_acquire+0x68/0x7c)
[<c0069394>] (lock_acquire+0x68/0x7c) from [<c04958f8>] (_raw_spin_lock_irqsave+0x48/0x5c)
[<c04958f8>] (_raw_spin_lock_irqsave+0x48/0x5c) from [<c0381e6c>] (clk_gate_endisable+0x28/0x88)
[<c0381e6c>] (clk_gate_endisable+0x28/0x88) from [<c0381ee0>] (clk_gate_enable+0xc/0x14)
[<c0381ee0>] (clk_gate_enable+0xc/0x14) from [<c0386c68>] (flexgen_enable+0x28/0x40)
[<c0386c68>] (flexgen_enable+0x28/0x40) from [<c037f260>] (__clk_enable+0x5c/0x9c)
[<c037f260>] (__clk_enable+0x5c/0x9c) from [<c037f558>] (clk_enable+0x18/0x2c)
[<c037f558>] (clk_enable+0x18/0x2c) from [<c064a1dc>] (st_lpc_of_register+0xc0/0x248)
[<c064a1dc>] (st_lpc_of_register+0xc0/0x248) from [<c0649e44>] (clocksource_of_init+0x34/0x58)
[<c0649e44>] (clocksource_of_init+0x34/0x58) from [<c0637ddc>] (sti_timer_init+0x10/0x18)
[<c0637ddc>] (sti_timer_init+0x10/0x18) from [<c06343f8>] (time_init+0x20/0x30)
[<c06343f8>] (time_init+0x20/0x30) from [<c0632984>] (start_kernel+0x20c/0x2e8)
[<c0632984>] (start_kernel+0x20c/0x2e8) from [<40008074>] (0x40008074)

Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: Gabriel Fernandez <gabriel.fernandez@linaro.org>
Fixes: b1165170 ("clk: st: STiH407: Support for Flexgen Clocks")
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>