This change is to allow access to the firmware block context in order to
give the firmware update callback implementation an indication of when
to reset the flash context. Additionally, it allows for a validity check
between the total expected size downloaded and the actual size
downloaded. A simple implementation can check if the block context's
current downloaded blocks is equal to the expected block size in order
to determine if the flash context needs to be reset. This approach
seemed the simplest, and knowing the firmware block context can have
other purposes. This has been tested by accessing the block context
during the update in the block received callback and confirming that the
callback had information regarding the current downloaded bytes.
Fixes#16122
Signed-off-by: Kyle Sun <yaomon18@yahoo.com>