xen/arm: Rename cpu_boot_data to system_cpuinfo
As we will sanitize the content of boot_cpu_data it will not really
contain the boot cpu information but the system sanitize information.
Rename the structure to system_cpuinfo so the user is informed that this
is the system wide available feature and not anymore the features of the
boot cpu.
The original boot cpu data is still available in cpu_data.
Signed-off-by: Bertrand Marquis <bertrand.marquis@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>