[PATCH 1/3] serial: make bugs field not specific to 8250 type uarts.

[Alan Cox]

> Make the bugs field part of the globally visible struct
> uart_port and remove the 8250 specific one.

Except all the bits in it are 8250 specific things or names that are
meaningless in generic form - no. I also don't want to encourage flags
and bug bits. We already have too many and its making the code a mess.
So right now we want less not more.