detect meru as a BMC-lite platform
Summary: We should automate this with platforms.json somehow but no time right now.
Test Plan:
Build & unit test:
```
0 ~/local/openbmc/tools/flashy $ ./build.sh && ./build_dev.sh && go test ./...
ok github.com/facebook/openbmc/tools/flashy (cached)
ok github.com/facebook/openbmc/tools/flashy/checks_and_remediations/bletchley (cached)
? github.com/facebook/openbmc/tools/flashy/flash_procedure [no test files]
ok github.com/facebook/openbmc/tools/flashy/checks_and_remediations/common (cached)
ok github.com/facebook/openbmc/tools/flashy/checks_and_remediations/galaxy100 (cached)
ok github.com/facebook/openbmc/tools/flashy/checks_and_remediations/wedge100 (cached)
ok github.com/facebook/openbmc/tools/flashy/checks_and_remediations/yamp (cached)
? github.com/facebook/openbmc/tools/flashy/lib/logger [no test files]
? github.com/facebook/openbmc/tools/flashy/utilities [no test files]
? github.com/facebook/openbmc/tools/flashy/tests [no test files]
ok github.com/facebook/openbmc/tools/flashy/install (cached)
ok github.com/facebook/openbmc/tools/flashy/lib/fileutils (cached)
ok github.com/facebook/openbmc/tools/flashy/lib/flash (cached)
ok github.com/facebook/openbmc/tools/flashy/lib/flash/flashcp (cached)
ok github.com/facebook/openbmc/tools/flashy/lib/flash/flashutils (cached)
ok github.com/facebook/openbmc/tools/flashy/lib/flash/flashutils/devices (cached)
ok github.com/facebook/openbmc/tools/flashy/lib/step (cached)
ok github.com/facebook/openbmc/tools/flashy/lib/utils (cached)
ok github.com/facebook/openbmc/tools/flashy/lib/validate (cached)
ok github.com/facebook/openbmc/tools/flashy/lib/validate/image (cached)
ok github.com/facebook/openbmc/tools/flashy/lib/validate/partition (cached)
```
Reviewed By: cjcon90
Differential Revision: D51814249
fbshipit-source-id: 45a3f7735178dd8aa5e44f3c5715e317b646d0a7
