cxl: docs/devices Fix typos and clarify wording in device-types.rst

cxl: docs/devices Fix typos and clarify wording in device-types.rst

Fix several typos and improve comment clarity in the CXL device types
docs:
 "w/" replaced with "with"
 "sill" -> "still"
 "The allows" -> "This allows"
 "capacity" corrected to "capable"
 "more devices" corrected to "more upstream devices" in MLD description

These changes improve readability and enhance the documentation quality.

[ dj: Fix up "one or more hosts" to "one or more upstream devices" from
      Gregory ]

Signed-off-by: Alok Tiwari <alok.a.tiwari@oracle.com>
Reviewed-by: Gregory Price <gourry@gourry.net>
Link: https://patch.msgid.link/20250616060737.1645393-1-alok.a.tiwari@oracle.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>