xfs: fix issues that cause userspace warnings

Some of the code shared with userspace causes compilation warnings
from things turned off in the kernel code, such as differences in
variable signedness. Fix those issues.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

diff --git a/fs/xfs/xfs_attr_remote.c b/fs/xfs/xfs_attr_remote.c
index b42926a..712a502 100644
--- a/fs/xfs/xfs_attr_remote.c
+++ b/fs/xfs/xfs_attr_remote.c
@@ -239,7 +239,7 @@
 	xfs_ino_t	ino,
 	int		*offset,
 	int		*valuelen,
-	char		**dst)
+	__uint8_t	**dst)
 {
 	char		*src = bp->b_addr;
 	xfs_daddr_t	bno = bp->b_bn;
@@ -286,7 +286,7 @@
 	xfs_ino_t	ino,
 	int		*offset,
 	int		*valuelen,
-	char		**src)
+	__uint8_t	**src)
 {
 	char		*dst = bp->b_addr;
 	xfs_daddr_t	bno = bp->b_bn;
@@ -339,7 +339,7 @@
 	struct xfs_mount	*mp = args->dp->i_mount;
 	struct xfs_buf		*bp;
 	xfs_dablk_t		lblkno = args->rmtblkno;
-	char			*dst = args->value;
+	__uint8_t		*dst = args->value;
 	int			valuelen = args->valuelen;
 	int			nmap;
 	int			error;
@@ -403,7 +403,7 @@
 	struct xfs_bmbt_irec	map;
 	xfs_dablk_t		lblkno;
 	xfs_fileoff_t		lfileoff = 0;
-	char			*src = args->value;
+	__uint8_t		*src = args->value;
 	int			blkcnt;
 	int			valuelen;
 	int			nmap;