arm, arm64: Fix selection of CONFIG_SCHED_THERMAL_PRESSURE

Qian reported that the current setup forgoes the Kconfig dependencies and
results in warnings such as:

  WARNING: unmet direct dependencies detected for SCHED_THERMAL_PRESSURE
    Depends on [n]: SMP [=y] && CPU_FREQ_THERMAL [=n]
    Selected by [y]:
    - ARM64 [=y]

Revert commit

  e17ae7fea8 ("arm, arm64: Select CONFIG_SCHED_THERMAL_PRESSURE")

and re-implement it by making the option default to 'y' for arm64 and arm,
which respects Kconfig dependencies (i.e. will remain 'n' if
CPU_FREQ_THERMAL=n).

Fixes: e17ae7fea8 ("arm, arm64: Select CONFIG_SCHED_THERMAL_PRESSURE")
Reported-by: Qian Cai <cai@lca.pw>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200729135718.1871-1-valentin.schneider@arm.com

arch/arm/Kconfig

@@ -46,7 +46,6 @@ config ARM
 	select EDAC_ATOMIC_SCRUB
 	select GENERIC_ALLOCATOR
 	select GENERIC_ARCH_TOPOLOGY if ARM_CPU_TOPOLOGY
-	select SCHED_THERMAL_PRESSURE if ARM_CPU_TOPOLOGY
 	select GENERIC_ATOMIC64 if CPU_V7M || CPU_V6 || !CPU_32v6K || !AEABI
 	select GENERIC_CLOCKEVENTS_BROADCAST if SMP
 	select GENERIC_CPU_AUTOPROBE

arch/arm64/Kconfig

@@ -192,7 +192,6 @@ config ARM64
 	select PCI_SYSCALL if PCI
 	select POWER_RESET
 	select POWER_SUPPLY
-	select SCHED_THERMAL_PRESSURE
 	select SPARSE_IRQ
 	select SWIOTLB
 	select SYSCTL_EXCEPTION_TRACE

init/Kconfig

@@ -493,6 +493,8 @@ config HAVE_SCHED_AVG_IRQ
 
 config SCHED_THERMAL_PRESSURE
 	bool
+	default y if ARM && ARM_CPU_TOPOLOGY
+	default y if ARM64
 	depends on SMP
 	depends on CPU_FREQ_THERMAL
 	help