selftests/bpf: Fix sk_bypass_prot_mem failure with 64K page

selftests/bpf: Fix sk_bypass_prot_mem failure with 64K page

The current selftest sk_bypass_prot_mem only supports 4K page.
When running with 64K page on arm64, the following failure happens:
  ...
  check_bypass:FAIL:no bypass unexpected no bypass: actual 3 <= expected 32
  ...
  #385/1   sk_bypass_prot_mem/TCP  :FAIL
  ...
  check_bypass:FAIL:no bypass unexpected no bypass: actual 4 <= expected 32
  ...
  #385/2   sk_bypass_prot_mem/UDP  :FAIL
  ...

Adding support to 64K page as well fixed the failure.

Cc: Kuniyuki Iwashima <kuniyu@google.com>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20260113061028.3798326-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>