sfc: Fix MCDI structure field lookup

The least significant bit number (LBN) of a field within an MCDI
structure is counted from the start of the structure, not the
containing dword.  In MCDI_ARRAY_FIELD() we need to mask it rather
than using the usual EFX_DWORD_FIELD() macro.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>

drivers/net/ethernet/sfc/mcdi.h

@@ -113,11 +113,13 @@ extern void efx_mcdi_sensor_event(struct efx_nic *efx, efx_qword_t *ev);
 #define MCDI_EVENT_FIELD(_ev, _field)			\
 	EFX_QWORD_FIELD(_ev, MCDI_EVENT_ ## _field)
 #define MCDI_ARRAY_FIELD(_buf, _field1, _type, _index, _field2)		\
-	EFX_DWORD_FIELD(						\
+	EFX_EXTRACT_DWORD(						\
 		*((efx_dword_t *)					\
 		  (MCDI_ARRAY_PTR(_buf, _field1, _type, _index) +	\
 		   (MC_CMD_ ## _type ## _TYPEDEF_ ## _field2 ## _OFST & ~3))), \
-		MC_CMD_ ## _type ## _TYPEDEF_ ## _field2)
+		MC_CMD_ ## _type ## _TYPEDEF_ ## _field2 ## _LBN & 0x1f, \
+		(MC_CMD_ ## _type ## _TYPEDEF_ ## _field2 ## _LBN & 0x1f) + \
+		MC_CMD_ ## _type ## _TYPEDEF_ ## _field2 ## _WIDTH - 1)
 
 extern void efx_mcdi_print_fwver(struct efx_nic *efx, char *buf, size_t len);
 extern int efx_mcdi_drv_attach(struct efx_nic *efx, bool driver_operating,