ARM: pmuv3: Add missing write_pmuacr()

ARM: pmuv3: Add missing write_pmuacr()

Fix compilation on Arm by adding missing static inline write_pmuacr()
declaration.

Fixes: 0bbff9ed8165 ("perf/arm_pmuv3: Add PMUv3.9 per counter EL0 access control")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202410291954.NiHLIwSC-lkp@intel.com/
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://lore.kernel.org/r/20241029120602.4061566-2-robh@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>