cleanup: remove nanokernel/nano leftovers

Signed-off-by: Anas Nashif <anas.nashif@intel.com>

arch/arm/core/cortex_m/reset.S

@@ -81,7 +81,7 @@ SECTION_SUBSEC_FUNC(TEXT,_reset_section,__start)
 
     /*
      * Set PSP and use it to boot without using MSP, so that it
-     * gets set to _interrupt_stack during nanoInit().
+     * gets set to _interrupt_stack during initialisation.
      */
     ldr r0, =_interrupt_stack
     ldr r1, =CONFIG_ISR_STACK_SIZE

arch/x86/core/crt0.S

@@ -252,7 +252,7 @@ __csSet:
 	 * dual-purposing of this area of memory is safe since
 	 * interrupts are disabled until the first context switch.
 	 *
-	 * nano_init.c enforces that the _interrupt_stack pointer and
+	 * kernel/init.c enforces that the _interrupt_stack pointer and
 	 * the ISR stack size are some multiple of STACK_ALIGN, which
 	 * is at least 4.
 	 *

include/net/buf.h

@@ -57,7 +57,7 @@ extern "C" {
  *  This is a simpler variant of the net_buf object (in fact net_buf uses
  *  net_buf_simple internally). It doesn't provide any kind of reference
  *  counting, user data, dynamic allocation, or in general the ability to
- *  pass through nano-kernel objects such as FIFOs.
+ *  pass through kernel objects such as FIFOs.
  *
  *  The main use of this is for scenarios where the meta-data of the normal
  *  net_buf isn't needed and causes too much overhead. This could be e.g.

samples/cpp_synchronization/src/main.cpp

@@ -42,10 +42,10 @@ K_THREAD_STACK_DEFINE(coop_stack, STACKSIZE);
 
 /*
  * @class cpp_semaphore
- * @brief nano semaphore
+ * @brief Semaphore
  *
  * Class derives from the pure virtual semaphore class and
- * implements it's methods for the nanokernel semaphore
+ * implements it's methods for the semaphore
  */
 class cpp_semaphore: public semaphore {
 protected:

tests/benchmarks/footprint/README.txt

@@ -79,9 +79,10 @@ minimal
 -------
 This configuration does NOT produce any output. To observe its operation,
 invoke it using gdb and observe that:
-- the kernel's timer ISR & main thread increment "K_LowTime" on a regular
-  basis
-- nano_cpu_idle() is invoked by the idle task each time K_LowTime is incremented
+- the kernel's timer ISR & main thread increment "_sys_clock_tick_count" on a
+  regular basis
+- k_cpu_idle() is invoked by the idle task each time _sys_clock_tick_count
+  is incremented
 
 regular
 -------

tests/kernel/sleep/src/sleep.c

@@ -6,7 +6,7 @@
 
 /*
  * @file
- * @brief Test nanokernel sleep and wakeup APIs
+ * @brief Test sleep and wakeup APIs
  *
  * This module tests the following sleep and wakeup scenarios:
  * 1. k_sleep() without cancellation

tests/kernel/workq/work_queue/README.txt

@@ -1,4 +1,4 @@
-Title: Test nano_work
+Title: Test workqeue APIs
 
 Description: