USB: ice40-hcd: Add retry for loading firmware

Add 3 retry for loading firmware so that if firmware load fails for first
time it will not fail loading of module. If loading of firmware fails for
3 time consecutively then this exits returning error code.

Change-Id: I8fc25383daf72917dc286b30121fbddc2282920c
Signed-off-by: Tarun Gupta <tarung@codeaurora.org>