drm/ttm: Add ttm_set_pages_wc and ttm_set_pages_uc helper

These two helpers will be used on set page caching.

Reviewed-by: Christian König <[e-mail]>
Signed-off-by: Huang Rui <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

include/drm/ttm/ttm_set_memory.h

···
 	return set_pages_wb(page, numpages);
 }
 
+static inline int ttm_set_pages_wc(struct page *page, int numpages)
+{
+	unsigned long addr = (unsigned long)page_address(page);
+
+	return set_memory_wc(addr, numpages);
+}
+
+static inline int ttm_set_pages_uc(struct page *page, int numpages)
+{
+	return set_pages_uc(page, numpages);
+}
+
 #else /* for CONFIG_X86 */
 
 #if IS_ENABLED(CONFIG_AGP)
···
 }
 
 #endif /* for CONFIG_AGP */
+
+static inline int ttm_set_pages_wc(struct page *page, int numpages)
+{
+	return 0;
+}
+
+static inline int ttm_set_pages_uc(struct page *page, int numpages)
+{
+	return 0;
+}
 
 #endif /* for CONFIG_X86 */