MA-15062-1 change names of MACROs used to boot MCU on imx8m devices

MA-15062-1 change names of MACROs used to boot MCU on imx8m devices

new imx8mn chips have Cortex-M7 inside, not like other imx8m devices
of imx8mm and imx8mq which have Cortex-M4 inside. the names of MACROs
used to boot MCU on imx8m devices is modified to make them more common
to cover M4 and M7.
annotations are also modified based on the differences between M4 and
M7.

Change-Id: Ida272e6ecdf577eeaadb9f1242f4524bd1014cac
Signed-off-by: faqiang.zhu <faqiang.zhu@nxp.com>
(cherry picked from commit eb825f8d4fbc2289b9ccf8f457fcba04922c8259)
(cherry picked from commit bd7599d2d34e55395423b4627bfc97eeb3ad742e)