sunrpc: convert to time64_t for expiry

Using signed 32-bit types for UTC time leads to the y2038 overflow,
which is what happens in the sunrpc code at the moment.

This changes the sunrpc code over to use time64_t where possible.
The one exception is the gss_import_v{1,2}_context() function for
kerberos5, which uses 32-bit timestamps in the protocol. Here,
we can at least treat the numbers as 'unsigned', which extends the
range from 2038 to 2106.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

include/linux/sunrpc/gss_api.h

@@ -48,7 +48,7 @@ int gss_import_sec_context(
 		size_t			bufsize,
 		struct gss_api_mech	*mech,
 		struct gss_ctx		**ctx_id,
-		time_t			*endtime,
+		time64_t		*endtime,
 		gfp_t			gfp_mask);
 u32 gss_get_mic(
 		struct gss_ctx		*ctx_id,
@@ -108,7 +108,7 @@ struct gss_api_ops {
 			const void		*input_token,
 			size_t			bufsize,
 			struct gss_ctx		*ctx_id,
-			time_t			*endtime,
+			time64_t		*endtime,
 			gfp_t			gfp_mask);
 	u32 (*gss_get_mic)(
 			struct gss_ctx		*ctx_id,