cpu log buffer size depends on cache line size

cpu log buffer size depends on cache line size

Platform may use specific cache line sizes. Since CACHE_WRITEBACK_GRANULE
defines the platform specific cache line size, it is used to define the
size of the cpu data structure CPU_DATA_SIZE aligned on cache line size.

Introduce assembly macro 'mov_imm' for AArch32 to simplify implementation
of function '_cpu_data_by_index'.

Change-Id: Ic2d49ffe0c3e51649425fd9c8c99559c582ac5a1
Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>