sysctl: avoid relocation error in debug builds
Avoids this error from ld when building with -DCMAKE_BUILD_TYPE=Debug:
/usr/lib/gcc/arm-none-eabi/14.2.1/../../../arm-none-eabi/bin/ld: CMakeFiles/sysctl.dir/src/pd_com.c.obj: in function `pd_tick':
src/pd_com.c:271:(.text.pd_tick+0x17a): undefined reference to `pd_set_fusb_switches1'
/usr/lib/gcc/arm-none-eabi/14.2.1/../../../arm-none-eabi/bin/ld: (pd_set_fusb_switches1): Unknown destination type (ARM/Thumb) in CMakeFiles/sysctl.dir/src/pd_com.c.obj
src/pd_com.c:271:(.text.pd_tick+0x17a): dangerous relocation: unsupported relocation
/usr/lib/gcc/arm-none-eabi/14.2.1/../../../arm-none-eabi/bin/ld: src/pd_com.c:253:(.text.pd_tick+0x1ea): undefined reference to `pd_set_fusb_switches1'
/usr/lib/gcc/arm-none-eabi/14.2.1/../../../arm-none-eabi/bin/ld: (pd_set_fusb_switches1): Unknown destination type (ARM/Thumb) in CMakeFiles/sysctl.dir/src/pd_com.c.obj
src/pd_com.c:253:(.text.pd_tick+0x1ea): dangerous relocation: unsupported relocation
/usr/lib/gcc/arm-none-eabi/14.2.1/../../../arm-none-eabi/bin/ld: src/pd_com.c:340:(.text.pd_tick+0x35c): undefined reference to `pd_set_fusb_switches1'
/usr/lib/gcc/arm-none-eabi/14.2.1/../../../arm-none-eabi/bin/ld: (pd_set_fusb_switches1): Unknown destination type (ARM/Thumb) in CMakeFiles/sysctl.dir/src/pd_com.c.obj
src/pd_com.c:340:(.text.pd_tick+0x35c): dangerous relocation: unsupported relocation
collect2: error: ld returned 1 exit status