Fix #110, adds #include hs_platform_cfg.h

[chillfig]

Checklist (Please check before submitting)

• I reviewed the Contributing Guide.
• I signed and emailed the appropriate Contributor License Agreement to GSFC-SoftwareRelease@mail.nasa.gov and copied cfs-program@lists.nasa.gov.

Describe the contribution

• Fixes hs_sysmon.c #includes hs_internal_cfg.h #110
  Replaces the #include hs_internal_cfg.h with #include hs_platform_cfg.h such that hs_sysmon.c is backward compatible with the original hs_platform_cfg.h file.

Testing performed
local machine build app and lcov

Expected behavior changes
No impact or behavior

System(s) tested on

• OS: Ubuntu 20.04

Additional context
N/A

Third party code
N/A

Contributor Info - All information REQUIRED for consideration of pull request
Justin Figueroa, Vantage Systems