mkbootimg: remove 'console=ttyAMA5' since it's appended on board revision
mkbootimg: remove 'console=ttyAMA5' since it's appended on board revision

remove 'console=ttyAMA5' from mkbootimg's command arguments. HiKey960 v1 uses
ttyAMA5, but v2 uses ttyAMA6.

Bootloader will read board type, and according to that, bootloader will
append console=ttyAMA5 or ttyAMA6 to kernel's cmdline. So, there is no
need add that in mkbootimg.

Signed-off-by: Guodong Xu <b3884af94c883a0fcbed2dca23baa11b986f7134@linaro.org>

96boards-hikey/tools-images-hikey960,96boards-hikey/tools-images-hikey960