cpus: Add casts to all definitions in CPU headers

There are some incorrect casts and some missing casts in the headers.
This patch fixes the ones that were 64-bit or 32-bit wide wrongly and
adds casts where they were missing.

Note that none of the changes of the patch actually changes the values
of the definitions. This patch is just for correctness.

Change-Id: Iad6458021bad521922ce4f91bafff38b116b49eb
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>