Slight improvements in Mbed TLS shared heap helpers
Slight improvements in Mbed TLS shared heap helpers

This patch, firstly, makes the error messages consistent to how printed
strings are usually formatted. Secondly, it removes an unnecessary #if
directive.

Change-Id: Idbb8ef0070562634766b683ac65f8160c9d109e6
Signed-off-by: John Tsichritzis <c5e6a94b5ed6b01ab911c6a4e005fdf814669fe4@arm.com>

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