cpufreq: fix memory leak in sun50i_cpufreq_nvmem_probe

```-----------------------------------------
unreferenced object 0xffff000010742a00 (size 128):
  comm "swapper/0", pid 1, jiffies 4294902015 (age 1187.652s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<00000000b4dfebaa>] __kmalloc+0x338/0x474
    [<00000000d6e716db>] sun50i_cpufreq_nvmem_probe+0xc4/0x36c
    [<000000007d6082a0>] platform_probe+0x98/0x11c
    [<00000000c990f549>] really_probe+0x234/0x5a0
    [<000000002d9fecc6>] __driver_probe_device+0x194/0x224
    [<00000000cf0b94fa>] driver_probe_device+0x64/0x13c
    [<00000000f238e4cf>] __device_attach_driver+0xf8/0x180
    [<000000006720e418>] bus_for_each_drv+0xf8/0x160
    [<00000000df4f14f6>] __device_attach+0x174/0x29c
    [<00000000782002fb>] device_initial_probe+0x20/0x30
    [<00000000c2681b06>] bus_probe_device+0xfc/0x110
    [<00000000964cf3bd>] device_add+0x5f0/0xcd0
    [<000000004b9264e3>] platform_device_add+0x198/0x390
    [<00000000fa82a9d0>] platform_device_register_full+0x178/0x210
    [<000000009a5daf13>] sun50i_cpufreq_init+0xf8/0x168
    [<000000000377cc7c>] do_one_initcall+0xe4/0x570
```

-----------------------------------------

if sun50i_cpufreq_get_efuse failed, then opp_tables leak.

Fixes: f328584f ("cpufreq: Add sun50i nvmem based CPU scaling driver")
Signed-off-by: Xiaobing Luo <luoxiaobing0926@gmail.com>
Reviewed-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

drivers/cpufreq/sun50i-cpufreq-nvmem.c

@@ -98,8 +98,10 @@ static int sun50i_cpufreq_nvmem_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	ret = sun50i_cpufreq_get_efuse(&speed);
-	if (ret)
+	if (ret) {
+		kfree(opp_tables);
 		return ret;
+	}
 
 	snprintf(name, MAX_NAME_LEN, "speed%d", speed);