gpu: fix filename case sensitivity

Signed-off-by: Stephen Gutekanst <stephen@hexops.com>

gpu/src/device.zig

@@ -0,0 +1,11 @@
+pub const Device = enum(usize) {
+    _,
+
+    // TODO: verify there is a use case for nullable value of this type.
+    pub const none: Device = @intToEnum(Device, 0);
+
+    pub const LostReason = enum(u32) {
+        undef = 0x00000000,
+        destroyed = 0x00000001,
+    };
+};