syscalls: mmap(): use unsigned offset type consistently

Most architectures that implement the old-style mmap() with byte offset
use 'unsigned long' as the type for that offset, but microblaze and
riscv have the off_t type that is shared with userspace, matching the
prototype in include/asm-generic/syscalls.h.

Make this consistent by using an unsigned argument everywhere. This
changes the behavior slightly, as the argument is shifted to a page
number, and an user input with the top bit set would result in a
negative page offset rather than a large one as we use elsewhere.

For riscv, the 32-bit sys_mmap2() definition actually used a custom
type that is different from the global declaration, but this was
missed due to an incorrect type check.

Signed-off-by: Arnd Bergmann <[e-mail]>

arch/csky/kernel/syscall.c

···
 	unsigned long, prot,
 	unsigned long, flags,
 	unsigned long, fd,
-	off_t, offset)
+	unsigned long, offset)
 {
 	if (unlikely(offset & (~PAGE_MASK >> 12)))
 		return -EINVAL;

arch/loongarch/kernel/syscall.c

···
 #define __SYSCALL(nr, call)	[nr] = (call),
 
 SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len, unsigned long,
-		prot, unsigned long, flags, unsigned long, fd, off_t, offset)
+		prot, unsigned long, flags, unsigned long, fd, unsigned long, offset)
 {
 	if (offset & ~PAGE_MASK)
 		return -EINVAL;

arch/microblaze/kernel/sys_microblaze.c

···
 
 SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
 		unsigned long, prot, unsigned long, flags, unsigned long, fd,
-		off_t, pgoff)
+		unsigned long, pgoff)
 {
 	if (pgoff & ~PAGE_MASK)
 		return -EINVAL;

arch/riscv/kernel/sys_riscv.c

···
 #ifdef CONFIG_64BIT
 SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
 	unsigned long, prot, unsigned long, flags,
-	unsigned long, fd, off_t, offset)
+	unsigned long, fd, unsigned long, offset)
 {
 	return riscv_sys_mmap(addr, len, prot, flags, fd, offset, 0);
 }
···
 #if defined(CONFIG_32BIT) || defined(CONFIG_COMPAT)
 SYSCALL_DEFINE6(mmap2, unsigned long, addr, unsigned long, len,
 	unsigned long, prot, unsigned long, flags,
-	unsigned long, fd, off_t, offset)
+	unsigned long, fd, unsigned long, offset)
 {
 	/*
 	 * Note that the shift for mmap2 is constant (12),

include/asm-generic/syscalls.h

···
 #ifndef sys_mmap
 asmlinkage long sys_mmap(unsigned long addr, unsigned long len,
 			unsigned long prot, unsigned long flags,
-			unsigned long fd, off_t pgoff);
+			unsigned long fd, unsigned long off);
 #endif
 
 #ifndef sys_rt_sigreturn