Fix signed/unsigned pointer warning

Commit 2ae83bf9 ("[CIFS] Fix setting time before epoch (negative
time values)") changed "u64 t" to "s64 t", which makes do_div() complain
about a pointer signedness mismatch:

      CC      fs/cifs/netmisc.o
    In file included from ./arch/mips/include/asm/div64.h:12:0,
                     from include/linux/kernel.h:124,
                     from include/linux/list.h:8,
                     from include/linux/wait.h:6,
                     from include/linux/net.h:23,
                     from fs/cifs/netmisc.c:25:
    fs/cifs/netmisc.c: In function ‘cifs_NTtimeToUnix’:
    include/asm-generic/div64.h:43:28: warning: comparison of distinct pointer types lacks a cast [enabled by default]
      (void)(((typeof((n)) *)0) == ((uint64_t *)0)); \
                                ^
    fs/cifs/netmisc.c:941:22: note: in expansion of macro ‘do_div’
       ts.tv_nsec = (long)do_div(t, 10000000) * 100;

Introduce a temporary "u64 abs_t" variable to fix this.
Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Signed-off-by: Steve French <steve.french@primarydata.com>

fs/cifs/netmisc.c

@@ -926,6 +926,7 @@ cifs_NTtimeToUnix(__le64 ntutc)
 
 	/* Subtract the NTFS time offset, then convert to 1s intervals. */
 	s64 t = le64_to_cpu(ntutc) - NTFS_TIME_OFFSET;
+	u64 abs_t;
 
 	/*
 	 * Unfortunately can not use normal 64 bit division on 32 bit arch, but
@@ -933,13 +934,14 @@ cifs_NTtimeToUnix(__le64 ntutc)
 	 * to special case them
 	 */
 	if (t < 0) {
-		t = -t;
-		ts.tv_nsec = (long)(do_div(t, 10000000) * 100);
+		abs_t = -t;
+		ts.tv_nsec = (long)(do_div(abs_t, 10000000) * 100);
 		ts.tv_nsec = -ts.tv_nsec;
-		ts.tv_sec = -t;
+		ts.tv_sec = -abs_t;
 	} else {
-		ts.tv_nsec = (long)do_div(t, 10000000) * 100;
-		ts.tv_sec = t;
+		abs_t = t;
+		ts.tv_nsec = (long)do_div(abs_t, 10000000) * 100;
+		ts.tv_sec = abs_t;
 	}
 
 	return ts;