kfifo: fix kerneldoc for kfifo_avail and kfifo_in_locked
kfifo: fix kerneldoc for kfifo_avail and kfifo_in_locked

Function argument is not having "len" anywhere;
"len" is later used in kfifo_{in|out}.

So here, it would be appropriate to say,
it copies @n bytes and not @len

Signed-off-by: Viral Mehta <7efa26344a1542c33ef508d0aa6c2b4b2b2a21a6@lntinfotech.com>
Signed-off-by: Jiri Kosina <ed58f755cc8caaf10c3e8c731a8b86fb8f13d6cb@suse.cz>

TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs