drm/panfrost: Prefix interrupt handlers' names

Currently, the interrupt lines requested by Panfrost
use unmeaningful names, which adds some obscurity
to interrupt introspection (i.e. any tool based
on procfs' interrupts file).

In order to improve this, prefix each requested
interrupt with the module name: panfrost-{gpu,job,mmu}.

Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20191214045952.9452-1-ezequiel@collabora.com