x86/hyper-v: Add "polling" bit to hv_synic_sint

That bit is documented in TLFS 5.0c as follows:

  Setting the polling bit will have the effect of unmasking an
  interrupt source, except that an actual interrupt is not generated.

Signed-off-by: Wei Liu <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Michael Kelley <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: liuw

arch/x86/include/asm/hyperv-tlfs.h

@@ -809,7 +809,8 @@ union hv_synic_sint {
 		u64 reserved1:8;
 		u64 masked:1;
 		u64 auto_eoi:1;
-		u64 reserved2:46;
+		u64 polling:1;
+		u64 reserved2:45;
 	} __packed;
 };