Rename LIB_ to LIBC_ for all libc Kconfig

[xiaoxiang781216]

Summary

follow other libc component naming convention

Impact

Follow up the kernel change: apache/nuttx#4267

Testing

Pass CI.

[gustavonihei]

LGTM

[acassis]

Seams like it broke the elf example:

elf_main.c: In function 'elf_main':
Error: elf_main.c:347:40: error: 'MOUNTPT' undeclared (first use in this function)
  347 |       snprintf(fullpath, 128, "%s/%s", MOUNTPT, dirlist[i]);
      |                                        ^~~~~~~
elf_main.c:347:40: note: each undeclared identifier is reported only once for each function it appears in
make[3]: *** [/github/workspace/sources/apps/Application.mk:192: elf_main.c.github.workspace.sources.apps.examples.elf.o] Error 1

[acassis]

All board profile needs to be updated: CONFIG_LIB_ENVPATH -> CONFIG_LIBC_ENVPATH

[xiaoxiang781216]

Yes, apache/nuttx#4267 should fixe this.