wimax/i2400m: SDIO specific TX queue's minimum buffer room for new message

This patch specifies the TX queue's minimum buffer room required to
accommodate one smallest SDIO payload.
Please refer the documentation in the code.
Signed-off-by: Prasanna S. Panchamukhi <prasannax.s.panchamukhi@intel.com>

drivers/net/wimax/i2400m/sdio.c

@@ -483,6 +483,13 @@ int i2400ms_probe(struct sdio_func *func,
 	sdio_set_drvdata(func, i2400ms);
 
 	i2400m->bus_tx_block_size = I2400MS_BLK_SIZE;
+	/*
+	 * Room required in the TX queue for SDIO message to accommodate
+	 * a smallest payload while allocating header space is 224 bytes,
+	 * which is the smallest message size(the block size 256 bytes)
+	 * minus the smallest message header size(32 bytes).
+	 */
+	i2400m->bus_tx_room_min = I2400MS_BLK_SIZE - I2400M_PL_ALIGN * 2;
 	i2400m->bus_pl_size_max = I2400MS_PL_SIZE_MAX;
 	i2400m->bus_setup = i2400ms_bus_setup;
 	i2400m->bus_dev_start = i2400ms_bus_dev_start;