Move console.c to pl011 specific driver location

Rename drivers/console/console.c to
drivers/arm/peripherals/pl011/pl011_console.c. This makes it clear
that this is a pl011 specific console implementation.

Fixes ARM-software/tf-issues#129

Change-Id: Ie2f8109602134c5b86993e32452c70734c45a3ed
Merge pull request #43 from danh-arm/dh/tf-issues#129

Move console.c to pl011 specific driver location