bpf: fix cbpf parser bug for octal numbers

Range is 0-7, not 0-9, otherwise parser silently excludes it from the
strtol() rather than throwing an error.

Reported-by: Marc Boschma <[e-mail]>
Signed-off-by: Daniel Borkmann <[e-mail]>
Acked-by: Alexei Starovoitov <[e-mail]>
Acked-by: Song Liu <[e-mail]>
Signed-off-by: Alexei Starovoitov <[e-mail]>

tools/bpf/bpf_exp.l

···
 			yylval.number = strtol(yytext, NULL, 10);
 			return number;
 		}
-([0][0-9]+)	{
+([0][0-7]+)	{
 			yylval.number = strtol(yytext + 1, NULL, 8);
 			return number;
 		}