kconfig: remove grammatically ambiguous option_error

This commit decreases 6 shift/reduce conflicts, and finally achieves
conflict-free parser.

Since Kconfig has no terminator for a config block, detecting the end
of config_stmt is not easy.

For example, there are two ways for handling the error in the following
code:

  1 config FOO
  2         =

 [A] Print "unknown option" error, assuming the line 2 is a part of
     config_option_list

 [B] Print "invalid statement", assuming the line 1 is reduced into
     a config_stmt by itself

Bison actually chooses [A] because it performs the shift rather than
the reduction where both are possible.

However, there is no reason to choose one over the other.

Let's remove the option_error, and let it fall back to [B].
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

scripts/kconfig/zconf.y

@@ -31,7 +31,6 @@ struct symbol *symbol_hash[SYMBOL_HASHSIZE];
 static struct menu *current_menu, *current_entry;
 
 %}
-%expect 6
 
 %union
 {
@@ -138,12 +137,6 @@ common_stmt:
 	| assignment_stmt
 ;
 
-option_error:
-	  T_WORD error T_EOL		{ zconf_error("unknown option \"%s\"", $1); }
-	| error T_EOL			{ zconf_error("invalid option"); }
-;
-
-
 /* config/menuconfig entry */
 
 config_entry_start: T_CONFIG nonconst_symbol T_EOL
@@ -180,7 +173,6 @@ config_option_list:
 	| config_option_list symbol_option
 	| config_option_list depends
 	| config_option_list help
-	| config_option_list option_error
 ;
 
 config_option: T_TYPE prompt_stmt_opt T_EOL
@@ -280,7 +272,6 @@ choice_option_list:
 	| choice_option_list choice_option
 	| choice_option_list depends
 	| choice_option_list help
-	| choice_option_list option_error
 ;
 
 choice_option: T_PROMPT prompt if_expr T_EOL
@@ -429,7 +420,6 @@ help: help_start T_HELPTEXT
 depends_list:
 	  /* empty */
 	| depends_list depends
-	| depends_list option_error
 ;
 
 depends: T_DEPENDS T_ON expr T_EOL