This is a minor extension of the commit 26ae69fd03 ("imx6: refresh
kernel config with 5.10 symbols"), with correct and full disable of
the Arm Cortex-A7 based i.MX 6UL and 6UL{L,Z} families support and
re-enable of the Cortex-A9 based i.MX 6L{S,X}.
Signed-off-by: Piotr Dymacz <pepe2k@gmail.com>