fcntl: rename F_OWNER_GID to F_OWNER_PGRP

This is for consistency with various ioctl() operations that include the
suffix "PGRP" in their names, and also for consistency with PRIO_PGRP,
used with setpriority() and getpriority(). Also, using PGRP instead of
GID avoids confusion with the common abbreviation of "group ID".

I'm fine with anything that makes it more consistent, and if PGRP is what
is the predominant abbreviation then I see no need to further confuse
matters by adding a third one.

Signed-off-by: Peter Zijlstra <[e-mail]>
Acked-by: Michael Kerrisk <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

fs/fcntl.c

···
 		type = PIDTYPE_PID;
 		break;
 
-	case F_OWNER_GID:
+	case F_OWNER_PGRP:
 		type = PIDTYPE_PGID;
 		break;
 
···
 		break;
 
 	case PIDTYPE_PGID:
-		owner.type = F_OWNER_GID;
+		owner.type = F_OWNER_PGRP;
 		break;
 
 	default:

include/asm-generic/fcntl.h

···
 
 #define F_OWNER_TID	0
 #define F_OWNER_PID	1
-#define F_OWNER_GID	2
+#define F_OWNER_PGRP	2
 
 struct f_owner_ex {
 	int	type;