You can move any Icon.
Just tap the icon, press the Blackberry button and choose
MOVE - to move the icon in the current folder
Move To Folder - to move the icon to another folder
Hide - to hide it
Delete - to delete it
Show All - to show hidden icon
So in your case, tap the Google map icon to hilight it - The press BB button - Chose move to folder and select home
Also remember that depending on your settings (whether you have 1 row to 3 rows set) in your main bb menu what you have placed in the first 1-3 (settings) rows will be what's on your home screen. So make sure that your google map icon is within a row that appears on your home screen. The folder briard was talking about (I think) is the main bb menu but that doesn't make it the home/front screen which is where OP wants their icon.
True, after moving the icon the 'Home' folder, you may have to move it again on another row in order to have it to show on the Home screen without scrolling.