fixed boot_snprintf, and nanoprintf linking bugs

[ZERICO2005]

boot_snprintf had a call to vnsprintf instead of boot_vnsprintf by mistake.

The user is unlikely to directly call vprintf or vfprintf, so they have been forced inlined into printf and fprintf. This saves space as code for vprintf and vfprintf won't need to be linked in most cases. I would've done this with vasprintf, and vsnprintf, but they are considerably larger

__attribute__((__always_inline__))
int _vprintf_c(const char *__restrict format, va_list vlist)
{
  return npf_vpprintf(npf_putc_std, NULL, format, vlist);
}

int _printf_c(char const *__restrict format, ...) {
  va_list va;
  va_start(va, format);
  int const rv = _vprintf_c(format, va);
  va_end(va);
  return rv;
}