mtd-utils: flash_otp_dump make offset optional

mtd-utils: flash_otp_dump make offset optional

Commit 0a5e2fa5c1e4 ("mtd-utils: add optional offset parameter to
flash_otp_dump") introduced an offset parameter. This should have
been optional, but there was a typo. Fix it.

Reported-by: Sergei Antonov <saproj@gmail.com>
Fixes: 0a5e2fa5c1e4 ("mtd-utils: add optional offset parameter to flash_otp_dump")
Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Sergei Antonov <saproj@gmail.com>
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>