Steps to Disable Private Browsing in Safari mobile browsers:
If the toolbar is not currently visible, tap once on the address bar to display it.

Read more : http://www.ehow.com/how_7689571_turn-safari-private-browsing-iphone.html
 
  1. Tap the "Tabs" button on Safari's toolbar to bring up the tab switcher screen.
Note: If the toolbar is not currently visible, tap once on the address bar to display it
  1. Tap "Private" to toggle Safari to Private mode.
  2. Tap either the "Plus" button or "Done" to open a blank tab and start browsing.
Note: If you've used private mode before and you left pages open, tapping the "Plus" button opens a blank tab, while tapping "Done" returns you to the last tab you had open; you can also tap any of the tabs in the tab switcher to open it.