arch/csky/kernel/probes/kprobes.c: fix bugon.cocci warnings

Use BUG_ON instead of a if condition followed by BUG.

Generated by: scripts/coccinelle/misc/bugon.cocci

Link: https://lkml.kernel.org/r/alpine.DEB.2.22.394.2107061049150.7197@hadrien
Fixes: 7d37cb2c

 ("lib: fix kconfig dependency on ARCH_WANT_FRAME_POINTERS")
Signed-off-by: kernel test robot <lkp@intel.com>
Signed-off-by: Julia Lawall <julia.lawall@inria.fr>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Julian Braha <julianbraha@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>