juno: Add clock HAL support

This patch adds the HAL clock configuration for
CDCEL937, HDLCD and the SoC clocks and add all the
different clocks to the build.

Change-Id: I84b7eaec1a626e1166dd02711869a2ae71ef8dcd
Signed-off-by: Elieva Pignat <Elieva.Pignat@arm.com>
Signed-off-by: Jim Quigley <jim.quigley@arm.com>
Signed-off-by: Raphael Gault <raphael.gault@arm.com>
Signed-off-by: Nicola Mazzucato <nicola.mazzucato@arm.com>