cxl/feature: Remove redundant code of get supported features

cxl/feature: Remove redundant code of get supported features

In cxlctl_get_supported_features(), there is a code block that handles
the case where the requested is equal to 0. But the code following the
code block can also handle this situation. So the code block is not
needed.

Signed-off-by: Li Ming <ming.li@zohomail.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Link: https://patch.msgid.link/20250516143220.35302-1-ming.li@zohomail.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>