Use Magic Erase Tool in Photoshop and adjust the Tolerance(Erase Range).
Or
Magic Wand Tool
Or
Go to Select option form the menu click "Load Selection" and again go to
Select option from the menu click "Color Range" then select your 
image's white area with the help of color picker and delete the selected area.

3 ways to do this:

Use Magic Erase Tool in Photoshop and adjust the Tolerance (Erase Range).

Or

Magic Wand Tool

Or

1. Go to Select option form the menu
2. Click "Load Selection"
3. Again go to Select option from the menu click "Color Range"
4. Select your image's white area with the help of color picker
5. Delete the selected area.

Use Magic Erase Tool in Photoshop and adjust the Tolerance(Erase Range). Or Magic Wand Tool

Use Magic Erase Tool in Photoshop and adjust the Tolerance(Erase Range).
Or
Magic Wand Tool
Or
Go to Select option form the menu click "Load Selection" and again go to
Select option from the menu click "Color Range" then select your 
image's white area with the help of color picker and delete the selected area.