pgsql: Rework macro pgstat_is_ioop_tracked_in_bytes()

Rework macro pgstat_is_ioop_tracked_in_bytes()

As written, it was triggering a compilation warning for old versions of
clang, as reported by buildfarm members ayu, batfish and demoiselle.
Forcing a cast with "unsigned int" should fix the warning.

While on it, the macro is moved to pgstat.h, closer to the declaration
of IOOp, per suggestion from Tom Lane.

Reported-by: Tom Lane
Reviewed-by: Bertrand Drouvot, Tom Lane, Nazir Bilal Yavuz
Discussion: https://postgr.es/m/1272824.1736961543@sss.pgh.pa.us

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/7b6468cc9523d7d923487d212281af51f7f3dae2

Modified Files
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src/backend/utils/activity/pgstat_io.c | 8 --------
src/include/pgstat.h | 4 ++++
2 files changed, 4 insertions(+), 8 deletions(-)