chtMultiRegionSimpleFoam: revert change to hEqn to support liquids

applications/solvers/heatTransfer/chtMultiRegionFoam/chtMultiRegionSimpleFoam/fluid/hEqn.H

@@ -5,8 +5,8 @@
       - fvm::Sp(fvc::div(phi), h)
       - fvm::laplacian(turb.alphaEff(), h)
      ==
-        fvc::div(phi/fvc::interpolate(rho), rho/psi, "div(U,p)")
-      - (rho/psi)*fvc::div(phi/fvc::interpolate(rho))
+        fvc::div(phi/fvc::interpolate(rho), p, "div(U,p)")
+      - p*fvc::div(phi/fvc::interpolate(rho))
       + rad.Sh(thermo)
     );