remove GPU clause for building zm

Author: whannah1

components/eamxx/src/physics/CMakeLists.txt

@@ -10,9 +10,7 @@ if (SCREAM_DOUBLE_PRECISION)
   add_subdirectory(cosp)
   add_subdirectory(tms)
   add_subdirectory(iop_forcing)
-  if (NOT EAMXX_ENABLE_GPU)
-    add_subdirectory(zm)
-  endif()
+  add_subdirectory(zm)
 else()
   message(STATUS "WARNING: RRTMGP, COSP, TMS, ZM, and IOPForcing only supported for double precision builds; skipping")
 endif()