trivial: style fixes

Signed-off-by: Curtis Millar <curtis.millar@data61.csiro.au>

Add constructor to set up heap before libc

The dynamic heap used by rumprun apps needs to be configured before libc
is initialised. The dynamic heap also depends on malloc, so it needs to
run after the vsyscall function has been configured.

Signed-off-by: Curtis Millar <curtis.millar@data61.csiro.au>

arm/clock: get time from timer interface

Added a check to get the clock time depending on the timer
configuration. Added support to optionally use the timer interface
interface 'time' function.

seL4: remove deleted arch_info function

seL4: Add new stdio platform support

A rumprun process may be initialised with existing stdio 'pipes' which
consist of circular buffers in shared memory and notification objects
for signalling the availability of data in the buffers.

seL4: Add way to register software event handlers

This makes it possible to register event handlers that will run attached
to a rumpkernel cpu context. This can be used to register event handlers
in custom rump kernel drivers that can receive notification messages
from other seL4 threads, not just hardware interrupts.

Remove hardware serial from seL4 rumprun platform

Instead, rely on being provided an endpoint to
contact a serial server on.
putc now buffers characters until the buffer is full, a
newline is printed or flush is explicitly called, at this point
it will IPC the serial server to print the contents of the buffer.

Use an ltimer backed by RPC instead of HW timer

Such that we can run multiple rump apps.

seL4: get IOAPIC pci interrupt numbers from config

IOAPIC interrupt numbers are supposed to be parsed out of ACPI tables.
We delegate this to the seL4 roottask to do this and tell us the
interrupt numbers that certain PCI devices should use.

seL4: Add missing include

seL4: Use new sel4platsupport timer API

seL4: run astyle over project

seL4: Add CAmkES support