Pull timer fixes from Thomas Gleixner:
 "A few small fixes for timer drivers:

   - Prevent infinite recursion in the arm architected timer driver with
     ftrace

   - Propagate error codes to the caller in case of failure in EM STI
     driver

   - Adjust a bogus loop iteration in the arm architected timer driver

   - Add a missing Kconfig dependency to the pistachio clocksource to
     prevent build failures

   - Correctly check for IS_ERR() instead of NULL in the shared timer-of
     code"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  clocksource/drivers/arm_arch_timer: Avoid infinite recursion when ftrace is enabled
  clocksource/drivers/Kconfig: Fix CLKSRC_PISTACHIO dependencies
  clocksource/drivers/timer-of: Checking for IS_ERR() instead of NULL
  clocksource/drivers/em_sti: Fix error return codes in em_sti_probe()
  clocksource/drivers/arm_arch_timer: Fix mem frame loop initialization