Clarify README for voice call tutorial app

samples/tutorials/voice/README.md

  * Make sure that you use a voice SIM and not a data SIM for this tutorial.
  * This tutorial only allows you to make a phone call from mangOH to another phone
  * Insert a headset audio jack into CN500 to listen to the audio
- * Mangoh must be registered on Network with the SIM in ready stat by entering `cm sim`
+ * Mangoh must be registered on Network with the SIM in ready state.
  * Make sure voiceCallService is started by entering: `app start voiceCallService`
  * Check "logread -f "
  * Execute app : app runProc  mangohVoiceCall --exe=mangohVoiceCall --  <Destination phone number>