x86: support enable CDP by boot parameter and add get CDP status

x86: support enable CDP by boot parameter and add get CDP status

Add boot parameter `psr=cdp` to enable CDP at boot time.
Intel Code/Data Prioritization (CDP) feature is based on CAT. Note that
cos_max would be half when CDP is on. struct psr_cat_cbm is extended to
support CDP operation. Extend psr_get_cat_l3_info sysctl to get CDP
status.

Signed-off-by: He Chen <he.chen@linux.intel.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Chao Peng <chao.p.peng@linux.intel.com>