Fix an NVHPC/25.9 compilation error in the CAM GPU regression test

[sjsprecious]

Description of changes

@cacraigucar identified a compilation error while running the CAM GPU regression test on Derecho. Reported in ESCOMP/CAM#1637. This seemed to be an NVHPC-specific issue but I was able to work around it by changing two lines in the CMEPS source code.

Specific notes

Contributors other than yourself, if any: N/A

CMEPS Issues Fixed (include github issue #):

Are changes expected to change answers? (specify if bfb, different at roundoff, more substantial) bfb

Any User Interface Changes (namelist or namelist defaults changes)? No

Testing performed

Please describe the tests along with the target model and machine(s)
If possible, please also added hashes that were used in the testing

ERS_Ln9.ne30pg3_ne30pg3_mt232.FHISTC_LTso.derecho_nvhpc.cam-outfrq9s_gpu_default test on Derecho.

[billsacks]

Thank you. I had deja vu here and realized that this is the same fix as in #668 ... I realized that PR was never merged because of ongoing discussion about the testing changes that were made there.

I'll merge this one.