ARM: 8602/1: factor out CSSELR/CCSIDR operations that use cp15 directly

Currently we use raw cp15 operations to access the cache setup data.

This patch abstracts the CSSELR and CCSIDR accessors out to a header so
that the implementation for them can be switched out as we do with other
cpu/cachetype operations.

Signed-off-by: Jonathan Austin <jonathan.austin@arm.com>
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Tested-by: Andras Szemzo <sza@esh.hu>
Tested-by: Joachim Eastwood <manabian@gmail.com>
Tested-by: Alexandre TORGUE <alexandre.torgue@st.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>