scoutfs: Tidy some enum usage

Prefer named to anonymous enums. This helps readability a little.

Use enum as param type if possible (a couple spots).

Remove unused enum in lock_server.c.

Define enum spbm_flags using shift notation for consistency.

Rename get_file_block()'s "gfb" parameter to "flags" for consistency.

Signed-off-by: Andy Grover <agrover@versity.com>

kmod/src/block.c

@@ -58,7 +58,7 @@ struct block_info {
 #define DECLARE_BLOCK_INFO(sb, name) \
 	struct block_info *name = SCOUTFS_SB(sb)->block_info
 
-enum {
+enum block_status_bits {
 	BLOCK_BIT_UPTODATE = 0,	/* contents consistent with media */
 	BLOCK_BIT_NEW,		/* newly allocated, contents undefined */
 	BLOCK_BIT_DIRTY,	/* dirty, writer will write */