remove duplicates of new generic bits/msg.h

arch/aarch64/bits/msg.h

-struct msqid_ds {
-	struct ipc_perm msg_perm;
-	time_t msg_stime;
-	time_t msg_rtime;
-	time_t msg_ctime;
-	unsigned long msg_cbytes;
-	msgqnum_t msg_qnum;
-	msglen_t msg_qbytes;
-	pid_t msg_lspid;
-	pid_t msg_lrpid;
-	unsigned long __pad1;
-	unsigned long __pad2;
-};

arch/mips64/bits/msg.h

-struct msqid_ds {
-	struct ipc_perm msg_perm;
-	time_t msg_stime;
-	time_t msg_rtime;
-	time_t msg_ctime;
-	unsigned long msg_cbytes;
-	msgqnum_t msg_qnum;
-	msglen_t msg_qbytes;
-	pid_t msg_lspid;
-	pid_t msg_lrpid;
-	unsigned long __pad1;
-	unsigned long __pad2;
-};

arch/powerpc64/bits/msg.h

-struct msqid_ds {
-	struct ipc_perm msg_perm;
-	time_t msg_stime;
-	time_t msg_rtime;
-	time_t msg_ctime;
-	unsigned long msg_cbytes;
-	msgqnum_t msg_qnum;
-	msglen_t msg_qbytes;
-	pid_t msg_lspid;
-	pid_t msg_lrpid;
-	unsigned long __unused[2];
-};

arch/riscv64/bits/msg.h

-struct msqid_ds {
-	struct ipc_perm msg_perm;
-	time_t msg_stime;
-	time_t msg_rtime;
-	time_t msg_ctime;
-	unsigned long msg_cbytes;
-	msgqnum_t msg_qnum;
-	msglen_t msg_qbytes;
-	pid_t msg_lspid;
-	pid_t msg_lrpid;
-	unsigned long __pad1;
-	unsigned long __pad2;
-};

arch/s390x/bits/msg.h

-struct msqid_ds {
-	struct ipc_perm msg_perm;
-	time_t msg_stime;
-	time_t msg_rtime;
-	time_t msg_ctime;
-	unsigned long msg_cbytes;
-	msgqnum_t msg_qnum;
-	msglen_t msg_qbytes;
-	pid_t msg_lspid;
-	pid_t msg_lrpid;
-	unsigned long __unused[2];
-};

arch/x86_64/bits/msg.h

-struct msqid_ds {
-	struct ipc_perm msg_perm;
-	time_t msg_stime;
-	time_t msg_rtime;
-	time_t msg_ctime;
-	unsigned long msg_cbytes;
-	msgqnum_t msg_qnum;
-	msglen_t msg_qbytes;
-	pid_t msg_lspid;
-	pid_t msg_lrpid;
-	unsigned long __unused[2];
-};