ARM: align cpu_method_of_table naming

The cpu_method_of_table is the oddball of the various OF linker sections.
In preparation to have common linker section definitions, align the
cpu_method_of_table with the other definitions for the naming and ending
with a blank struct.

Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rob Herring <robh@kernel.org>
Cc: Russell King <linux@arm.linux.org.uk>