lmb: notify of any changes to the LMB memory map

lmb: notify of any changes to the LMB memory map

In U-Boot, LMB and EFI are two primary modules who provide memory
allocation and reservation API's. Both these modules operate with the
same regions of memory for allocations. Use the LMB memory map update
event to notify other interested listeners about a change in it's
memory map. This can then be used by the other module to keep track of
available and used memory.

There is no need to send these notifications when the LMB module is
being unit-tested. Add a flag to the lmb structure to indicate if the
memory map is being used for tests, and suppress sending any
notifications when running these unit tests.

Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>