timeout: Fix up API usage

Kernel timeouts have always been a 32 bit integer despite the
existence of generation macros, and existing code has been
inconsistent about using them.  Upcoming commits are going to make the
timeout arguments opaque, so fix things up to be rigorously correct.
Changes include:

+ Adding a K_TIMEOUT_EQ() macro for code that needs to compare timeout
  values for equality (e.g. with K_FOREVER or K_NO_WAIT).

+ Adding a k_msleep() synonym for k_sleep() which can continue to take
  integral arguments as k_sleep() moves away to timeout arguments.

+ Pervasively using the K_MSEC(), K_SECONDS(), et. al. macros to
  generate timeout arguments.

+ Removing the usage of K_NO_WAIT as the final argument to
  K_THREAD_DEFINE().  This is just a count of milliseconds and we need
  to use a zero.

This patch include no logic changes and should not affect generated
code at all.

Signed-off-by: Andy Ross <andrew.j.ross@intel.com>

include/sys_clock.h

@@ -53,6 +53,8 @@ extern void z_enable_sys_clock(void);
 /* number of nanoseconds per second */
 #define NSEC_PER_SEC ((NSEC_PER_USEC) * (USEC_PER_MSEC) * (MSEC_PER_SEC))
 
+#define k_msleep(ms) k_sleep(ms)
+#define K_TIMEOUT_EQ(a, b) ((a) == (b))
 
 /* kernel clocks */