serial/stm32: add support for IRQ APIs

The patch extends STM32 serial port driver with support for IRQ API of
the common UART port driver API.

Change-Id: If105e8528ea4ed4181cc4af0c97c24aa874e69e0
Origin: Original
Signed-off-by: Maciej Borzecki <maciek.borzecki@gmail.com>
3 files changed