RTEMS build broken

[jphickey]

Describe the bug
Needs updates to fix issues related to OS_Milli2Ticks

• Missing prototype
• References to old function prototype still exist in some RTEMS source files.

To Reproduce
Build default configuration for RTEMS 4.11. Fails to compile with errors such as:

/home/joe/code/cfecfs/github/osal/src/os/rtems/src/os-impl-countsem.c: In function 'OS_CountSemTimedWait_Impl':
/home/joe/code/cfecfs/github/osal/src/os/rtems/src/os-impl-countsem.c:212:5: error: implicit declaration of function 'OS_Milli2Ticks' [-Werror=implicit-function-declaration]
     TimeInTicks = OS_Milli2Ticks(msecs);
     ^

Expected behavior
Should compile cleanly.

System observed on:
Ubuntu 20.04 (host) cross buiding for RTEMS 4.11.3 / pc-686 BSP

Additional context
Typo noted in #614 but there are more problems than just that....

Reporter Info
Joseph Hickey, Vantage Systems, Inc.