cxl/acpi: Return 'rc' instead of '0' in cxl_parse_cfmws()

Driver initialization returned success (return 0) even if the
initialization (cxl_decoder_add() or acpi_table_parse_cedt()) failed.

Return the error instead of swallowing it.

Fixes: f4ce1f76

 ("cxl/acpi: Convert CFMWS parsing to ACPI sub-table helpers")
Signed-off-by: Breno Leitao <leitao@debian.org>
Link: https://lore.kernel.org/r/20230714093146.2253438-2-leitao@debian.org
Reviewed-by: Alison Schofield <alison.schofield@intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>