dmaengine: ti: k3-udma: Set rflow count for BCDMA split channels

commit 46a63aa808ec1cbfc5a7953b5c11061cba140e39 from
git://git.ti.com/ti-linux-kernel/ti-linux-kernel.git

BCDMA RX channels have one flow per channel, therefore set the rflow_cnt
to rchan_cnt.

Without this patch, request for BCDMA RX channel allocation fails as
rflow_cnt is 0 thus fails to reserve a rflow for the channel.

Fixes: 88448980

 ("dmaengine: ti: k3-udma: Add support for BCDMA channel TPL handling")
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Signed-off-by: Xulin Sun <xulin.sun@windriver.com>