Not able to compile cam7 physics with nag compiler

### What happened?

Build of cam7 physics with the nag compiler on izumi failed.

These are the compiler error messages:

```
Error: /home/fvitt/camdev/cam6_4_047/src/physics/rrtmgp/ext/extensions/mo_cloud_sampling.F90, line 315: Implicit type for FINDLOC in SAMPLED_MASK_EXP_RAN
Error: /home/fvitt/camdev/cam6_4_047/src/physics/rrtmgp/ext/extensions/mo_cloud_sampling.F90, line 315: Implicit type for FINDLOC in SAMPLED_MASK_MAX_RAN
```

It seems that `findloc` intrinsic function is not available in nag6.2

### What are the steps to reproduce the bug?

```
./create_test --test-id cam7 SMS_D_Ln9.ne3pg3_ne3pg3_mg37.FMTHIST.izumi_nag.cam-outfrq9s
```

### What CAM tag were you using?

cam6_4_047

### What machine were you running CAM on?

CGD machine (e.g. izumi)

### What compiler were you using?

NAG

### Path to a case directory, if applicable

/scratch/cluster/fvitt/SMS_D_Ln9.ne3pg3_ne3pg3_mg37.FMTHIST.izumi_nag.cam-outfrq9s.cam7

### Will you be addressing this bug yourself?

No

### Extra info

Perhaps nag7.0 will include the `findloc` function