genksyms: rename m_abstract_declarator to abstract_declarator

This is called "abstract-declarator" in K&R. [1]

I am not sure what "m_" stands for, but the name is clear enough
without it.

No functional changes are intended.

[1] https://cs.wmich.edu/~gupta/teaching/cs4850/sumII06/The%20syntax%20of%20C%20in%20Backus-Naur%20form.htm

Signed-off-by: Masahiro Yamada <[e-mail]>
Acked-by: Nicolas Schier <[e-mail]>

scripts/genksyms/parse.y

···
 	;
 
 parameter_declaration:
-	decl_specifier_seq m_abstract_declarator
+	decl_specifier_seq abstract_declarator
 		{ $$ = $2 ? $2 : $1; }
 	;
 
-m_abstract_declarator:
-	ptr_operator m_abstract_declarator
+abstract_declarator:
+	ptr_operator abstract_declarator
 		{ $$ = $2 ? $2 : $1; }
-	| direct_m_abstract_declarator
+	| direct_abstract_declarator
 	;
 
-direct_m_abstract_declarator:
+direct_abstract_declarator:
 	/* empty */					{ $$ = NULL; }
 	| IDENT
 		{ /* For version 2 checksums, we don't want to remember
···
 		{ remove_node($1);
 		  $$ = $1;
 		}
-	| direct_m_abstract_declarator '(' parameter_declaration_clause ')'
+	| direct_abstract_declarator '(' parameter_declaration_clause ')'
 		{ $$ = $4; }
-	| direct_m_abstract_declarator '(' error ')'
+	| direct_abstract_declarator '(' error ')'
 		{ $$ = $4; }
-	| direct_m_abstract_declarator BRACKET_PHRASE
+	| direct_abstract_declarator BRACKET_PHRASE
 		{ $$ = $2; }
-	| '(' m_abstract_declarator ')'
+	| '(' abstract_declarator ')'
 		{ $$ = $3; }
 	| '(' error ')'
 		{ $$ = $3; }