Revert "defconfig: arm64: Disable DEVMEM and DEVKMEM for sdm845"

This reverts commit daf39399.

Official VTS testing uses performance builds, so this change
is not necessary.  And it negatively impacts some testing
teams.  Therefore revert this config change.

CRs-Fixed: 2135035
Change-Id: I8dc6db37d2fb453b799c081a4b6e6eca92cfe471
Signed-off-by: Bruce Levy <blevy@codeaurora.org>