virt: Further improve detection of EC2 metal instances

virt: Further improve detection of EC2 metal instances

Commit f90eea7d18d9ebe88e6a66cd7a86b618def8945d
virt: Improve detection of EC2 metal instances

Added support for detecting EC2 metal instances via the product
name in DMI by testing for the ".metal" suffix.

Unfortunately this doesn't cover all cases, as there are going to be
instance types where ".metal" is not a suffix (ie, .metal-16xl,
.metal-32xl, ...)

This modifies the logic to also allow those new forms.

Signed-off-by: Benjamin Herrenschmidt <benh@amazon.com>