ARM: 8788/1: ftrace: remove old mcount support

Commit cafa0010 ("Raise the minimum required gcc version to 4.6")
raised the minimum GCC version to 4.6. Old mcount is only required for
GCC versions older than 4.4.0. Hence old mcount support can be dropped
too.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>