Debian: CVE-2021-47455: linux -- security update

In the Linux kernel, the following vulnerability has been resolved:

ptp: Fix possible memory leak in ptp_clock_register()

I got memory leak as follows when doing fault injection test:

unreferenced object 0xffff88800906c618 (size 8):
comm "i2c-idt82p33931", pid 4421, jiffies 4294948083 (age 13.188s)
hex dump (first 8 bytes):
70 74 70 30 00 00 00 00 ptp0....
backtrace:
[] __kmalloc_track_caller+0x19f/0x3a0
[] kvasprintf+0xb5/0x150
[] kvasprintf_const+0x60/0x190
[] kobject_set_name_vargs+0x56/0x150
[] dev_set_name+0xc0/0x100
[] ptp_clock_register+0x9f4/0xd30 [ptp]
[] idt82p33_probe.cold+0x8b6/0x1561 [ptp_idt82p33]

When posix_clock_register() returns an error, the name allocated
in dev_set_name() will be leaked, the put_device() should be used
to give up the device reference, then the name will be freed in
kobject_cleanup() and other memory will be freed in ptp_clock_release().