Blackfin: debug-mmrs: prevent macro arg from expanding

Passing a non-simple expression in as the addr arg could incorrectly
apply the pointer cast resulting in misbehavior.  Add proper paren.
Signed-off-by: NMike Frysinger <vapier@gentoo.org>

arch/blackfin/kernel/debug-mmrs.c

@@ -27,7 +27,7 @@
 #define PORT_MUX BFIN_PORT_MUX
 #endif
 
-#define _d(name, bits, addr, perms) debugfs_create_x##bits(name, perms, parent, (u##bits *)addr)
+#define _d(name, bits, addr, perms) debugfs_create_x##bits(name, perms, parent, (u##bits *)(addr))
 #define d(name, bits, addr)         _d(name, bits, addr, S_IRUSR|S_IWUSR)
 #define d_RO(name, bits, addr)      _d(name, bits, addr, S_IRUSR)
 #define d_WO(name, bits, addr)      _d(name, bits, addr, S_IWUSR)