[PATCH] m68k: let clk_enable() return immediately if clk is NULL

[Defang Bo]

Similar to commit<742859adc721>("m68k: let clk_disable() return immediately if 
clk is NULL").
there should be a check for clk to prevent NULL pointer dereference.

Signed-off-by: Defang Bo <bodef...@126.com>
---
 arch/m68k/coldfire/clk.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/m68k/coldfire/clk.c b/arch/m68k/coldfire/clk.c
index 7bc666e..6decd11 100644
--- a/arch/m68k/coldfire/clk.c
+++ b/arch/m68k/coldfire/clk.c
@@ -90,6 +90,9 @@ EXPORT_SYMBOL(clk_get);
 int clk_enable(struct clk *clk)
 {
        unsigned long flags;
+       if (!clk)
+               return -EINVAL;
+
        spin_lock_irqsave(&clk_lock, flags);
        if ((clk->enabled++ == 0) && clk->clk_ops)
                clk->clk_ops->enable(clk);
-- 
2.7.4