imx95_evk: Restore support for i.MX95 A0 silicon

imx95_evk: Restore support for i.MX95 A0 silicon

This patch is used to restore support for i.MX95 A0 silicon. To avoid
duplicating defconfig, imx95.config is added and can be shared between
imx95_a0_19x19_evk_defconfig and imx95_19x19_evk_defconfig.

container.cfg and imximage.cfg are used to created .cfgout files that
are be passed to mkimage with -n to build flash.bin. Now they have been
deleted and replaced by adding their content to properties of node which
type is nxp-imx9image under binman node.

Fixes: 9936724aa9b ("imx95_evk: Add i.MX95 B0 support")
Signed-off-by: Alice Guo <alice.guo@nxp.com>
Tested-By: Tim Harvey <tharvey@gateworks.com> # imx95-19x19-evk (rA0)