examples: Fix disksnoop
examples: Fix disksnoop

Kernel commit 24b83deb29b ("block: move struct request to blk-mq.h")
and be6bfe36db17 ("block: inline hot paths of blk_account_io_*()")
introduce changes which break disksnoop.

Like #3748 and #3877 but for disksnoop, this commit fixes those issues.

Closes #3825.

Signed-off-by: Hengqi Chen <2146682b4c3fe4aa97c809745b7d5be9e6165e06@outlook.com>

iovisor/bcc,iovisor/bcc,iovisor/bcc,iovisor/bcc,iovisor/bcc