real loop indexes used in mbpf

[dkokron]

GDIT is testing a static analysis tool called Codee (https://www.codee.com/). Codee flagged some issues with mgbf.

codee: error: failed to analyze '/lfs/h1/hpc/support/USER/Projects/GSI/develop/src/mgbf/mg_input.f90'

error: Semantic errors in /lfs/h1/hpc/support/USER/Projects/GSI/develop/src/mgbf/mg_input.f90
/lfs/h1/hpc/support/USER/Projects/GSI/develop/src/mgbf/mg_input.f90:67:12: error: Must have INTEGER type, but is REAL(4)
V(n,m)=ampl*(mgimax0+ng)
^
/lfs/h1/hpc/support/USER/Projects/GSI/develop/src/mgbf/mg_input.f90:67:14: error: Must have INTEGER type, but is REAL(4)
V(n,m)=ampl(mgimax0+ng)
^
/lfs/h1/hpc/support/USER/Projects/GSI/develop/src/mgbf/mg_input.f90:145:12: error: Must have INTEGER type, but is REAL(4)
V(l,n,m)=ampl(mgimax0+ng) +(l-1)incrm
^
/lfs/h1/hpc/support/USER/Projects/GSI/develop/src/mgbf/mg_input.f90:145:14: error: Must have INTEGER type, but is REAL(4)
V(l,n,m)=ampl(mgimax0+ng) +(l-1)incrm
^
/lfs/h1/hpc/support/USER/Projects/GSI/develop/src/mgbf/mg_input.f90:145:16: error: Must have INTEGER type, but is REAL(4)
V(l,n,m)=ampl(mg*imax0+ng) +(l-1)*incrm

The l,n,m variables are loop indexes but they are declared.
real(i_kind):: ng,mg,L,m,n

[TingLei-NOAA]

@dkokron Thanks for this validation effort. The apparent fix is to use " integer(i_kind)" to replace "real(i_kind)".
I think you can direct make a PR for this or I can do it if you prefer.
Please let me know how you want to proceed. Thanks.
BTW: it is mgbf rather than "mbpf".

[dkokron]

@TingLei-NOAA Please submit the PR for this issue.