Cloud overlap computation in mcica_subcol_gen_lw.1col.f90 for icld 4 and 5 are identical

[Xeenych]

case (4) and case(5) are identical

RRTMG_LW/src/mcica_subcol_gen_lw.1col.f90

Line 577 in 6e8786a

case(5)

[mjiacono]

This is not an error, but the blocks of code for case (4), exponential cloud overlap, and case (5), exponential-random cloud overlap, in subroutine generate_stochastic_clouds could be consolidated here, since the stochastic procedure for these two cases is identical at this stage. The distinction between exponential and exponential-random cloud overlap is built into the alpha parameter, which is generated by subroutine get_alpha prior to its use in this stochastic procedure.