arch/topology: Fix variable naming to avoid shadowing

Using 'hw_pressure' for local variable name is confusing in regard to the
per-CPU 'hw_pressure' variable that uses the same name:

  include/linux/arch_topology.h:DECLARE_PER_CPU(unsigned long, hw_pressure);

... which puts it into a global scope for all code that includes
<linux/topology.h>, shadowing the local variable.

Rename it to avoid compiler confusion & Sparse warnings.

[ mingo: Expanded the changelog. ]

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20240425073709.379016-1-vincent.guittot@linaro.org
Closes: https://lore.kernel.org/oe-kbuild-all/202404250740.VhQQoD7N-lkp@intel.com/
Fixes: d4dbc991 ("sched/cpufreq: Rename arch_update_thermal_pressure() => arch_update_hw_pressure()")
Tested-by: Konrad Dybcio <konrad.dybcio@linaro.org> # QC SM8550 QRD