Use getin_p instead of getin

[Ehouarn Millour]

Some cleanup in the physics is needed (mainly in conf_phys_m.F90): get rid of using "getin" via an intermediate var_omp variable read by the OpenMP master and then copied to "var" for all threads, e.g.:

!$OMP MASTER
var_omp=... ! default value
call getin('var', var_omp)
!$OMP END MASTER
!$OMP BARRIER
var=var_omp

No need to declare an intermediate var_omp variable, and all the above can be replaced by:

var=... ! default value
call getin_p("var",var)