defaultenv-2: Fix verbose booting

During option parsing we use the variable BOOT_BOOTMOPTS, all other
scripts use BOOT_BOOTM_OPTS though. Fix this by using the same variable
everywhere.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
ubimkvol: Typo fix

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>