bpf, x64: clean up retpoline emission slightly

Make the RETPOLINE_{RA,ED}X_BPF_JIT() a bit more readable by
cleaning up the macro, aligning comments and spacing.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

arch/x86/include/asm/nospec-branch.h

@@ -301,7 +301,7 @@ do {									\
  *    jmp *%edx for x86_32
  */
 #ifdef CONFIG_RETPOLINE
-#ifdef CONFIG_X86_64
+# ifdef CONFIG_X86_64
 #  define RETPOLINE_RAX_BPF_JIT_SIZE	17
 #  define RETPOLINE_RAX_BPF_JIT()				\
 do {								\
@@ -314,7 +314,7 @@ do {								\
 	EMIT4(0x48, 0x89, 0x04, 0x24); /* mov %rax,(%rsp) */	\
 	EMIT1(0xC3);             /* retq */			\
 } while (0)
-#else
+# else /* !CONFIG_X86_64 */
 #  define RETPOLINE_EDX_BPF_JIT()				\
 do {								\
 	EMIT1_off32(0xE8, 7);	 /* call do_rop */		\
@@ -326,17 +326,16 @@ do {								\
 	EMIT3(0x89, 0x14, 0x24); /* mov %edx,(%esp) */		\
 	EMIT1(0xC3);             /* ret */			\
 } while (0)
-#endif
+# endif
 #else /* !CONFIG_RETPOLINE */
-
-#ifdef CONFIG_X86_64
+# ifdef CONFIG_X86_64
 #  define RETPOLINE_RAX_BPF_JIT_SIZE	2
 #  define RETPOLINE_RAX_BPF_JIT()				\
 	EMIT2(0xFF, 0xE0);       /* jmp *%rax */
-#else
+# else /* !CONFIG_X86_64 */
 #  define RETPOLINE_EDX_BPF_JIT()				\
 	EMIT2(0xFF, 0xE2)        /* jmp *%edx */
-#endif
+# endif
 #endif
 
 #endif /* _ASM_X86_NOSPEC_BRANCH_H_ */