This bug occurs when the davinci serial code tries to register UART(X) when
UART(X-1) or UART(X-2) is not enabled in the structure uart_config of the board
setup code:

This works: .enabled_uarts = (1 << 0)
This works: .enabled_uarts = (1 << 0) | (1 << 1)
This works: .enabled_uarts = (1 << 0) | (1 << 1) | | (1 << 2)
This fails: .enabled_uarts = (1 << 1)
This fails: .enabled_uarts = (1 << 1) | (1 << 2)
This fails: .enabled_uarts = (1 << 0) | (1 << 2)

The bug is triggered by the fact that the 8250 serial driver stops parsing the
serial_platform_data structure as soon as it sees a zero flags entry. Thus the
davinci serial registration code (serial.c) must <pack> the serial_platform_data
structure and only clear the flags entry when there is no more devices following.

Tested on DM6446 and DM355 custom boards.
Signed-off-by: Hugo Villeneuve <hugo@hugovil.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>