Fix typo in documentation page title
Fix typo in documentation page title

Change-Id: I426ffc8717757e35e556f675162a729ba095b7d5
Signed-off-by: John Tsichritzis <c5e6a94b5ed6b01ab911c6a4e005fdf814669fe4@arm.com>

achingupta/arm-trusted-firmware,achingupta/arm-trusted-firmware