usb: musb: tusb6010_omap: Do not reset the other direction's packet size

usb: musb: tusb6010_omap: Do not reset the other direction's packet size

BugLink: http://bugs.launchpad.net/bugs/1694621
commit 6df2b42f7c040d57d9ecb67244e04e905ab87ac6 upstream.

We have one register for each EP to set the maximum packet size for both
TX and RX.
If for example an RX programming would happen before the previous TX
transfer finishes we would reset the TX packet side.

To fix this issue, only modify the TX or RX part of the register.

Fixes: 550a7375fe72 ("USB: Add MUSB and TUSB support")
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>