uart: remove uart_irq_get()

This API is not being used for anything, the interrupts for UART
drivers are all being configured statically. Saves code space as
gc-sections can't tell that these APIs are unused.

Some instances where IRQ/priority information was being saved in
data structures and never used fixed.

Change-Id: If56b4fdc251b80be9094ffcbac6f61e265ac2ffd
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
8 files changed