libnvdimm, btt: fix format string warnings

Fix format warnings (seen on i386) in nvdimm/btt.c:

../drivers/nvdimm/btt.c: In function ‘btt_map_init’:
../drivers/nvdimm/btt.c:430:3: warning: format ‘%lx’ expects argument of type ‘long unsigned int’, but argument 4 has type ‘size_t’ [-Wformat=]
   dev_WARN_ONCE(to_dev(arena), size < 512,
   ^
../drivers/nvdimm/btt.c: In function ‘btt_log_init’:
../drivers/nvdimm/btt.c:474:3: warning: format ‘%lx’ expects argument of type ‘long unsigned int’, but argument 4 has type ‘size_t’ [-Wformat=]
   dev_WARN_ONCE(to_dev(arena), size < 512,
   ^

Fixes: 86652d2eb347 ("libnvdimm, btt: clean up warning and error messages")
Reported-by: Arnd Bergmann <arnd@arndb.de>
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/nvdimm/btt.c

@@ -428,7 +428,7 @@ static int btt_map_init(struct arena_info *arena)
 		size_t size = min(mapsize, chunk_size);
 
 		dev_WARN_ONCE(to_dev(arena), size < 512,
-			"chunk size: %#lx is unaligned\n", size);
+			"chunk size: %#zx is unaligned\n", size);
 		ret = arena_write_bytes(arena, arena->mapoff + offset, zerobuf,
 				size, 0);
 		if (ret)
@@ -472,7 +472,7 @@ static int btt_log_init(struct arena_info *arena)
 		size_t size = min(logsize, chunk_size);
 
 		dev_WARN_ONCE(to_dev(arena), size < 512,
-			"chunk size: %#lx is unaligned\n", size);
+			"chunk size: %#zx is unaligned\n", size);
 		ret = arena_write_bytes(arena, arena->logoff + offset, zerobuf,
 				size, 0);
 		if (ret)