ltp: fix warnings in "aio-stress.c"

In "testcases/kernel/io/ltp-aiodio/aio-stress.c" there are a number
of warnings that show up due to mismatches between fprintf()
conversion specifications and the variables being formatted.

Fix most of these by casting the variables to the right type; in one
case a "%td" is used to signify a ptrdiff_t variable.

Updated to address comments made by Garrett Cooper in review.
However, both "file_size" and "context_offset" variables represent
file offsets, and therefore should remain type off_t (rather than
size_t, which was recommended).  Some printf() formats were adjusted
to use %ld/(long) for printing off_t values.  Also updated some
whitespace, and now use "I/O" consistently, as requested.

Signed-off-by: Alex Elder <aelder@sgi.com>
1 file changed