ARM: 7682/1: cache-l2x0: fix masking of RTL revision numbering and set_debug init

Commit b8db6b88 (ARM: 7547/4: cache-l2x0: add support for Aurora L2 cache
ctrl) moved the masking of the part ID which caused the RTL version to be
lost. Commit 6248d060 (ARM: 7545/1: cache-l2x0: make outer_cache_fns a
field of l2x0_of_data) changed how .set_debug is initialized. Both commits
break commit 74ddcdb8 (ARM: 7608/1: l2x0: Only set .set_debug
on PL310 r3p0 and earlier) which uses the RTL version to conditionally set
.set_debug function pointer. Commit b8db6b88

 also caused the printed cache
ID to be missing the version information.

Fix this by reverting how the part number is masked so the RTL version
info is maintained. The cache-id-part DT property does not set the RTL
bits so masking them should have no effect. Also, re-arrange the order
of the function pointer init so the .set_debug function can be overridden.

Reported-by: Paolo Pisati <paolo.pisati@canonical.com>
Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Cc: Gregory CLEMENT <gregory.clement@free-electrons.com>
Cc: Yehuda Yitschak <yehuday@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>