### Description - Type: Bug - Priority: Minor TRNG implementation for NUMAKER_PFM_NUC472 with GCC throws compilation warnings: ``` [Warning] trng_api.c@89,27: comparison between signed and unsigned integer expressions [-Wsign-compare] ``` --------------------------------------------------------------- ## Bug **Target** NUMAKER_PFM_NUC472 **Toolchain:** GCC_ARM **Toolchain version:** 5.4.1 20160609 **mbed-cli version:** 0.9.10 **meed-os sha:** fc1f439 Merge pull request #3323 from andreaslarssonublox/ublox_odin_w2_drivers_update **Expected behavior** There should be no warnings **Actual behavior** Compiler outputs: ``` Compile [ 97.5%]: trng_api.c [Warning] trng_api.c@89,27: comparison between signed and unsigned integer expressions [-Wsign-compare] ``` **Steps to reproduce** mbed compile -m NUMAKER_PFM_NUC472 -t GCC_ARM