nak: Add better is_blackwell*() helpers

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/35795>

src/nouveau/compiler/nak/ir.rs

@@ -8769,10 +8769,20 @@ pub trait ShaderModel {
     }
 
     #[allow(dead_code)]
-    fn is_blackwell(&self) -> bool {
+    fn is_blackwell_a(&self) -> bool {
         self.sm() >= 100 && self.sm() < 110
     }
 
+    #[allow(dead_code)]
+    fn is_blackwell_b(&self) -> bool {
+        self.sm() >= 120 && self.sm() < 130
+    }
+
+    #[allow(dead_code)]
+    fn is_blackwell(&self) -> bool {
+        self.is_blackwell_a() || self.is_blackwell_b()
+    }
+
     fn num_regs(&self, file: RegFile) -> u32;
     fn hw_reserved_gprs(&self) -> u32;
     fn crs_size(&self, max_crs_depth: u32) -> u32;