drm/ttm: Use the BIT macro for the TTM_TT_FLAGs

New code is recommended to use the BIT macro instead of the explicit
shifts. Change the older defines so that we can keep the style consistent
with upcoming changes.

v2:
- Also change the value of the _PRIV_POPULATED bit (Christian König)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230307144621.10748-4-thomas.hellstrom@linux.intel.com

include/drm/ttm/ttm_tt.h

@@ -83,12 +83,12 @@ struct ttm_tt {
 	 * set by TTM after ttm_tt_populate() has successfully returned, and is
 	 * then unset when TTM calls ttm_tt_unpopulate().
 	 */
-#define TTM_TT_FLAG_SWAPPED		(1 << 0)
-#define TTM_TT_FLAG_ZERO_ALLOC		(1 << 1)
-#define TTM_TT_FLAG_EXTERNAL		(1 << 2)
-#define TTM_TT_FLAG_EXTERNAL_MAPPABLE	(1 << 3)
+#define TTM_TT_FLAG_SWAPPED		BIT(0)
+#define TTM_TT_FLAG_ZERO_ALLOC		BIT(1)
+#define TTM_TT_FLAG_EXTERNAL		BIT(2)
+#define TTM_TT_FLAG_EXTERNAL_MAPPABLE	BIT(3)
 
-#define TTM_TT_FLAG_PRIV_POPULATED  (1U << 31)
+#define TTM_TT_FLAG_PRIV_POPULATED	BIT(4)
 	uint32_t page_flags;
 	/** @num_pages: Number of pages in the page array. */
 	uint32_t num_pages;