ice_dyn_evp: pass 'grid_location' for LKD seabed stress on C grid

When the C grid support was added in 078aab4 (Merge cgridDEV branch
including C grid implementation and other fixes (#715), 2022-05-10),
subroutine ice_dyn_shared::seabed_stress_factor_LKD gained a
'grid_location' optional argument to indicate where to compute
intermediate quantities and the seabed stress itself (originally added
in 0f9f48b (ice_dyn_shared: add optional 'grid_location' argument to
seabed_stress_factor_LKD, 2021-11-17)). This argument was however
forgotten in ice_dyn_evp::evp when this subroutine was adapted for the C
grid in 48c07c6 (ice_dyn_evp: compute seabed stress factor at CD-grid
locations, 2021-11-17), such that currently the seabed stress is not
computed at the correct grid location for the C and CD grids.

Fix that by correctly passing the 'grid_location' argument. Note that
the dummy argument is incorrectly declared as 'intent(inout)' in the
subroutine, so change that to 'intent(in)' so we can pass in character
constants.

Closes: #891

cicecore/cicedyn/dynamics/ice_dyn_evp.F90

@@ -763,12 +763,14 @@ subroutine evp (dt)
                                                  icellE    (iblk),                 &
                                                  indxEi  (:,iblk), indxEj(:,iblk), &
                                                  vice  (:,:,iblk), aice(:,:,iblk), &
-                                                 hwater(:,:,iblk), TbE (:,:,iblk))
+                                                 hwater(:,:,iblk), TbE (:,:,iblk), &
+                                                 grid_location='E')
                   call seabed_stress_factor_LKD (nx_block        , ny_block,       &
                                                  icellN    (iblk),                 &
                                                  indxNi  (:,iblk), indxNj(:,iblk), &
                                                  vice  (:,:,iblk), aice(:,:,iblk), &
-                                                 hwater(:,:,iblk), TbN (:,:,iblk))
+                                                 hwater(:,:,iblk), TbN (:,:,iblk), &
+                                                 grid_location='N')
                enddo
                !$OMP END PARALLEL DO
 

cicecore/cicedyn/dynamics/ice_dyn_shared.F90

@@ -1289,7 +1289,7 @@ subroutine seabed_stress_factor_LKD (nx_block, ny_block,         &
       real (kind=dbl_kind), dimension (nx_block,ny_block), intent(inout) :: &
          TbU           ! seabed stress factor at 'grid_location' (N/m^2)
 
-      character(len=*), optional, intent(inout) :: &
+      character(len=*), optional, intent(in) :: &
          grid_location ! grid location (U, E, N), U assumed if not present
 
       real (kind=dbl_kind) :: &