kernel: Remove redundant TICKLESS_IDLE_SUPPORTED option

This flag is no longer necessary and TICKLESS_IDLE will be
enabled by default if SYS_POWER_MANAGEMENT is enabled.

Jira: ZEP-1325
Change-Id: Ic6cd4b8dc0a17c6a413cabf6509b215a4558318d
Signed-off-by: Ramesh Thomas <ramesh.thomas@intel.com>

arch/Kconfig

@@ -20,7 +20,6 @@ config ARM
 
 config X86
 	bool "x86 architecture"
-	select TICKLESS_IDLE_SUPPORTED
 	select ATOMIC_OPERATIONS_BUILTIN
 
 config NIOS2

arch/arc/Kconfig

@@ -41,7 +41,6 @@ menu "ARCv2 Family Options"
 config	CPU_ARCV2
 	bool
 	default y
-	select TICKLESS_IDLE_SUPPORTED
 	help
 	  This option signifies the use of a CPU of the ARCv2 family.
 

drivers/timer/Kconfig

@@ -143,7 +143,6 @@ config NRF_RTC_TIMER
 	bool "nRF Real Time Counter (NRF_RTC1) Timer"
 	default y
 	depends on SOC_FAMILY_NRF5 && CLOCK_CONTROL_NRF5
-	select TICKLESS_IDLE_SUPPORTED
 	help
 	This module implements a kernel device driver for the nRF Real Time
 	Counter NRF_RTC1 and provides the standard "system clock driver"

kernel/Kconfig

@@ -147,12 +147,6 @@ config NUM_DYNAMIC_TIMERS
 	Number of timers available for dynamic allocation via the
 	k_timer_alloc()/k_timer_free() API.
 
-config TICKLESS_IDLE_SUPPORTED
-	bool
-	default n
-	help
-	To be selected by an architecture if it does support tickless idle.
-
 config ERRNO
 	bool
 	prompt "Enable errno support"

kernel/Kconfig.power_mgmt

@@ -58,7 +58,7 @@ config DEVICE_POWER_MANAGEMENT
 config TICKLESS_IDLE
 	bool
 	prompt "Tickless idle"
-	default y if TICKLESS_IDLE_SUPPORTED
+	default y
 	help
 	This option suppresses periodic system clock interrupts whenever the
 	kernel becomes idle. This permits the system to remain in a power