Update install guide to note SystemReady Machines
The fedora install guide mentions that its for AMD/Intel machines
but much of this process also directly applies 1:1 with the Arm
SBSA/SBBR/SystemReady class of machines which utilize industry
standard HW/SW in the form of UEFI/ACPI/etc. Lets
mention those alongside the AMD/Intel when appropriate.
Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>