Revert "tools: libxc: flush data cache after loading images into guest memory"

Revert "tools: libxc: flush data cache after loading images into guest memory"

This reverts commit a0035ecc0d82c1d4dcd5e429e2fcc3192d89747a.

Even with this fix there is a period between the flush and the unmap where
processor may speculate data into the cache. The solution is to map this
region uncached or to use the HCR.DC bit to mark all guest accesses cached.
89eb02c2204a "xen: arm: force guest memory accesses to cacheable when MMU is
disabled" has arranged to do the latter.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>