fix sparse warning in horizon atm driver.

[Dave Jones <davej@redhat.com>]

these vars get fed u32's, and are OR'd with u32's.
Chances are they were meant to be u32's.

I don't have hardware to test this, but I can't fathom
why a u16 would be used here.

drivers/atm/horizon.c:1564:12: warning: cast truncates bits from constant value (40000000 becomes 0)
drivers/atm/horizon.c:1565:12: warning: cast truncates bits from constant value (40000000 becomes 0)
drivers/atm/horizon.c:1569:12: warning: cast truncates bits from constant value (80000000 becomes 0)
drivers/atm/horizon.c:1570:12: warning: cast truncates bits from constant value (80000000 becomes 0)

Signed-off-by: Dave Jones <davej@redhat.com>

--- linus/drivers/atm/horizon.c~	2005-11-09 00:51:50.000000000 -0500
+++ linus/drivers/atm/horizon.c	2005-11-09 00:55:36.000000000 -0500
@@ -1511,8 +1511,8 @@ static inline short setup_idle_tx_channe
     // a.k.a. prepare the channel and remember that we have done so.
     
     tx_ch_desc * tx_desc = &memmap->tx_descs[tx_channel];
-    u16 rd_ptr;
-    u16 wr_ptr;
+    u32 rd_ptr;
+    u32 wr_ptr;
     u16 channel = vcc->channel;
     
     unsigned long flags;