media: renesas: rzg2l-cru: Simplify FIFO empty check

Collapse FIFO empty helper into a single return statement by removing the
redundant `if (amnfifopntr_w == amnfifopntr_r_y) return true;` path. Make
`rzg2l_fifo_empty()` directly return `amnfifopntr_w == amnfifopntr_r_y`
to improve readability without changing behavior.

Reported-by: Dan Carpenter <[e-mail]>
Closes: https://lore.kernel.org/all/[e-mail]/
Signed-off-by: Lad Prabhakar <[e-mail]>
Reviewed-by: Laurent Pinchart <[e-mail]>
Reviewed-by: Geert Uytterhoeven <[e-mail]>
Reviewed-by: Tommaso Merciai <[e-mail]>
Tested-by: Tommaso Merciai <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Laurent Pinchart <[e-mail]>
Signed-off-by: Hans Verkuil <[e-mail]>

drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c

···
 	amnfifopntr_w = amnfifopntr & AMnFIFOPNTR_FIFOWPNTR;
 	amnfifopntr_r_y =
 		(amnfifopntr & AMnFIFOPNTR_FIFORPNTR_Y) >> 16;
-	if (amnfifopntr_w == amnfifopntr_r_y)
-		return true;
 
 	return amnfifopntr_w == amnfifopntr_r_y;
 }