remove microblaze user.h incorrectly copied from arm

arch/microblaze/bits/user.h

-struct user_fpregs_struct
-{
-	struct fp_reg {
-		unsigned sign1:1;
-		unsigned unused:15;
-		unsigned sign2:1;
-		unsigned exponent:14;
-		unsigned j:1;
-		unsigned mantissa1:31;
-		unsigned mantissa0:32;
-	} fpregs[8];
-	unsigned fpsr:32;
-	unsigned fpcr:32;
-	unsigned char ftype[8];
-	unsigned int init_flag;
-};
-
-struct user_regs_struct
-{
-	unsigned long uregs[18];
-};
-
-struct user
-{
-	struct user_regs_struct		regs;
-	int				u_fpvalid;
-	unsigned long			u_tsize;
-	unsigned long			u_dsize;
-	unsigned long			u_ssize;
-	unsigned long			start_code;
-	unsigned long			start_stack;
-	long				signal;
-	int				reserved;
-	struct user_regs_struct		*u_ar0;
-	unsigned long int		magic;
-	char				u_comm[32];
-	int				u_debugreg[8];
-	struct user_fpregs_struct	u_fp;
-	struct user_fpregs_struct	*u_fp0;
-};
+/* FIXME: missing in kernel? */