Remove remaining register code.

[mondalaci]

/home/laci/projects/firmware/right/src/macros/commands.c: In function 'processRepeatForCommand':
/home/laci/projects/firmware/right/src/macros/commands.c:1439:27: warning: implicit declaration of function 'validReg' [-Wimplicit-function-declaration]
 1439 |         bool regIsValid = validReg(idx, ctx->at);
      |                           ^~~~~~~~
/home/laci/projects/firmware/right/src/macros/commands.c:1444:17: error: 'regs' undeclared (first use in this function)
 1444 |             if (regs[idx] > 0) {
      |                 ^~~~
/home/laci/projects/firmware/right/src/macros/commands.c:1444:17: note: each undeclared identifier is reported only once for each function it appears in
make: *** [../../scripts/Makedefs.mk:220: build_make//home/laci/projects/firmware/right/src/macros/commands.o] Error 1

[kareltucek]

Fixed.