cxl: Remove duplicate #defines

These defines are not used, but other equivalent definitions
(CXL_SPA_SW_CMD_*) are used. Remove the unused defines.

Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>