tools: parse to enable new rdm policy parameters

tools: parse to enable new rdm policy parameters

This patch parses to enable user configurable parameters to specify
RDM resource and according policies which are defined previously,

Global RDM parameter:
    rdm = "strategy=host,policy=strict/relaxed"
Per-device RDM parameter:
    pci = [ 'sbdf, rdm_policy=strict/relaxed' ]

Default per-device RDM policy is same as default global RDM policy as being
'relaxed'. And the per-device policy would override the global policy like
others.

CC: Ian Jackson <ian.jackson@eu.citrix.com>
CC: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
CC: Ian Campbell <ian.campbell@citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>