docs: printk-formats: update size-casting examples

Since commit 72deb455

 ("block: remove CONFIG_LBDAF") sector_t and
blkcnt_t types are no longer variable in size, making them unsuitable
examples for casting to the largest possible type. This patch replaces
such examples with cycles_t and blk_status_t types, whose sizes depend
on architecture and config options respectively.

Signed-off-by: Carlos Llamas <cmllamas@google.com>
Link: https://lore.kernel.org/r/20210609195058.3518943-1-cmllamas@google.com


Signed-off-by: Jonathan Corbet <corbet@lwn.net>