kernel/bpf/: Fix misspellings using codespell tool

A typo is found out by codespell tool in 34th lines of hashtab.c:

$ codespell ./kernel/bpf/
./hashtab.c:34 : differrent ==> different

Fix a typo found by codespell.

Signed-off-by: Liu xuzhi <[e-mail]>
Signed-off-by: Alexei Starovoitov <[e-mail]>
Link: https://lore.kernel.org/bpf/[e-mail]

kernel/bpf/hashtab.c

···
 /*
  * The bucket lock has two protection scopes:
  *
- * 1) Serializing concurrent operations from BPF programs on differrent
+ * 1) Serializing concurrent operations from BPF programs on different
  *    CPUs
  *
  * 2) Serializing concurrent operations from BPF programs and sys_bpf()