fs/resctrl: Consider sparse masks when initializing new group's allocation

fs/resctrl: Consider sparse masks when initializing new group's allocation

A new resource group is intended to be created with sane defaults. For a cache
resource this means all cache portions the new group could possibly allocate
into. This includes unused cache portions and shareable cache portions used by
other groups and hardware.

New resource group creation does not take sparse masks into account. After
determining the bitmask reflecting the new group's possible allocations the
bitmask is forced to be contiguous even if the system supports sparse masks.
For example, a new group could by default allocate into a large portion of
cache represented by 0xff0f, but it is instead created with a mask of 0xf.

Do not force a contiguous allocation range if the system supports sparse masks.

Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://patch.msgid.link/abbbb008bc09d982d715e79d3b885c10f92c64e0.1763426240.git.reinette.chatre@intel.com