ARM: 8754/1: NOMMU: Move PMSAv7 MPU under it's own namespace

We are going to support different MPU which programming model is not
compatible to PMSAv7, so move PMSAv7 MPU under it's own namespace.

Tested-by: Szemz? András <sza@esh.hu>
Tested-by: Alexandre TORGUE <alexandre.torgue@st.com>
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>