juno: Provide sub-set of sensors

This patch adds a compile-time option to enable
the ful lset of sensors. By default, a subset is use
without affecting the functionality of the platform.

This is introduced to gain back some space in memory.

Change-Id: I7a203d7cf09b4c6ac7ca1af951f73ad155ba71bb
Signed-off-by: Nicola Mazzucato <nicola.mazzucato@arm.com>