clk: zynqmp: fix memory leak in zynqmp_register_clocks

clk: zynqmp: fix memory leak in zynqmp_register_clocks

This is detected by kmemleak running on zcu102 board:

unreferenced object 0xffffffc877e48180 (size 128):
comm "swapper/0", pid 1, jiffies 4294892909 (age 315.436s)
hex dump (first 32 bytes):
64 70 5f 76 69 64 65 6f 5f 72 65 66 5f 64 69 76 dp_video_ref_div
31 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 1...............
backtrace:
[<00000000c9be883b>] __kmalloc_track_caller+0x200/0x380
[<00000000f02c3809>] kvasprintf+0x7c/0x100
[<00000000e51dde4d>] kasprintf+0x60/0x80
[<0000000092298b05>] zynqmp_register_clocks+0x29c/0x398
[<00000000faaff182>] zynqmp_clock_probe+0x3cc/0x4c0
[<000000005f5986f0>] platform_drv_probe+0x58/0xa8
[<00000000d5810136>] really_probe+0xd8/0x2a8
[<00000000f5b671be>] driver_probe_device+0x5c/0x100
[<0000000038f91fcf>] __device_attach_driver+0x98/0xb8
[<000000008a3f2ac2>] bus_for_each_drv+0x74/0xd8
[<000000001cb2783d>] __device_attach+0xe0/0x140
[<00000000c268031b>] device_initial_probe+0x24/0x30
[<000000006998de4b>] bus_probe_device+0x9c/0xa8
[<00000000647ae6ff>] device_add+0x3c0/0x610
[<0000000071c14bb8>] of_device_add+0x40/0x50
[<000000004bb5d132>] of_platform_device_create_pdata+0xbc/0x138

This is because that when num_nodes is larger than 1, clk_out is
allocated using kasprintf for these nodes but only the last node's
clk_out is freed.

Signed-off-by: Quanyang Wang <quanyang.wang@windriver.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Tejas Patel <tejas.patel@xilinx.com>
Signed-off-by: Jolly Shah <jolly.shah@xilinx.com>
Link: https://lkml.kernel.org/r/1583185843-20707-5-git-send-email-jolly.shah@xilinx.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>