Fix #2590, Use proper printf format for size_t

[pepepr08]

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 #2590 Change the printf format so that the GAISLER RCC compiler doesn't warn about using the incorrect format for printing a size_t variable.

Testing performed
Steps taken to test the contribution:

1. make distclean && make TARGET=devboard BUILDTYPE=release OMIT_DEPRECATED=true RTEMS_NO_SHELL=false ENABLE_UNIT_TESTS=true -j install

Expected behavior changes
Fully compile

System(s) tested on

• Hardware: [e.g. PC, SP0, MCP750]
• OS: [e.g. Ubuntu 18.04, RTEMS 4.11, VxWorks 6.9]
• Versions: [e.g. cFE 6.6, OSAL 4.2, PSP 1.3 for mcp750, any related apps or tools]

Additional context
Add any other context about the contribution here.

Third party code
If included, identify any third party code and provide text file of license

Contributor Info - All information REQUIRED for consideration of pull request
Full name and company/organization/center of all contributors ("Personal" if individual work)

• Note CLAs apply to only software contributions.