These are three improvements / fixes for the arm_global_timer driver.
Changes from v2 at [1]:
- add patches 1 and 2 (which is why this is now a series instead of a
single patch) as in the code review process more issues have been
spotted that need fixing
- remove "psv < 0" check from patch 3 (as this check is now impossible
as patch 2 makes the variable in question an unsigned long with a
check for zero and returning before decrementing psv).
Changes from v1 at [0]:
- use FIELD_FIT() to check whether psv overflows the register
- update the description accordingly