powerpc: mpc8xx: Reorganise init RAM

Using SMC relocation microcode patch or USB-SOF microcode patch
will disable DPRAM memory from 0x2000 to 0x2400 and from 0x2f00
to 0x3000.

At the time being, init RAM is setup to use 0x2800-0x2e00, but
the stack pointer goes beyond 0x2800 and even beyond 0x2400.

For the time being we are not going to use any microcode patch
that uses memory about 0x3000, so reorganise setup to use:
- 0x2800 - 0x2e00 for init malloc and global data and CPM buffers
- 0x3000 - 0x3c00 for init stack

For more details about CPM dual port ram, see
commit b1d62424cb ("powerpc: mpc8xx: redistribute data in CPM dpram")

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>

board: MCR3000: Modernise the settings to properly work on lastest u-boot version

Both U-boot and Linux kernel have grown over the last releases
and don't fit anymore in the 2M EPROM of the board.

So, rework the setup to allow storing the Linux kernel image
on the UBIFS NAND Flash.

Also add support to FIT images as this is what the Linux kernel
look like nowadays.

Also increase CFG_SYS_BOOTMAPSZ to 32Mbytes and define
CONFIG_SYS_BOOTM_LEN with the same value, otherwise it defaults
to 8M which is not sufficient anymore with nowadays Linux kernels.

And set the netmask to 255.255.255.0 as a class C address is used.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: FRANJOU Stephane <stephane.franjou@csgroup.eu>

board: MCR3000: Migrate to using CONFIG_EXTRA_ENV_TEXT

We can move all of the environment changes to come
from CONFIG_EXTRA_ENV_TEXT.

Suggested-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>

board: MCR3000: Use lowercase filenames

Rename MCR3000.* to mcr3000.* to be more in line with
other boards.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>

board: MCR3000: Modernise the settings to properly work on lastest u-boot version

Both U-boot and Linux kernel have grown over the last releases
and don't fit anymore in the 2M EPROM of the board.

So, rework the setup to allow storing the Linux kernel image
on the UBIFS NAND Flash.

Also add support to FIT images as this is what the Linux kernel
look like nowadays.

Also increase CFG_SYS_BOOTMAPSZ to 32Mbytes and define
CONFIG_SYS_BOOTM_LEN with the same value, otherwise it defaults
to 8M which is not sufficient anymore with nowadays Linux kernels.

And set the netmask to 255.255.255.0 as a class C address is used.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: FRANJOU Stephane <stephane.franjou@csgroup.eu>

board: MCR3000: Migrate to using CONFIG_EXTRA_ENV_TEXT

We can move all of the environment changes to come
from CONFIG_EXTRA_ENV_TEXT.

Suggested-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>

board: MCR3000: Use lowercase filenames

Rename MCR3000.* to mcr3000.* to be more in line with
other boards.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>