powerpc/cell: Use fallthrough;

Convert the various uses of fallthrough comments to fallthrough;
Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/03073a9a269010ca439e9e658629c44602b0cc9f.1583896348.git.joe@perches.com

arch/powerpc/platforms/cell/spufs/switch.c

@@ -177,7 +177,7 @@ static inline void save_mfc_cntl(struct spu_state *csa, struct spu *spu)
 		POLL_WHILE_FALSE((in_be64(&priv2->mfc_control_RW) &
 				  MFC_CNTL_SUSPEND_DMA_STATUS_MASK) ==
 				 MFC_CNTL_SUSPEND_COMPLETE);
-		/* fall through */
+		fallthrough;
 	case MFC_CNTL_SUSPEND_COMPLETE:
 		if (csa)
 			csa->priv2.mfc_control_RW =