LU-10026 sptlrpc: don't crash for too-large chunk size

LU-10026 sptlrpc: don't crash for too-large chunk size

If the chunk size is too large, don't fall off the
end of the page_pool[] array with a large "order".

EX-bug-id: EX-8270
Test-Parameters: trivial
Fixes: d945f1b064 ("EX-6261 ptlrpc: extend sec bulk functionality")
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Signed-off-by: Artem Blagodarenko <ablagodarenko@ddn.com>
Change-Id: I9cdf059860cab3c22857766dba5617358f0aaba9
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/57845
Reviewed-by: Sergey Cheremencev <scherementsev@ddn.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>