powerpc/configs: Remove dead symbols

Remove references to symbols that no longer exist as reported by
scripts/checkkconfigsymbols.py.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200724131728.1643966-2-mpe@ellerman.id.au

mtd: rawnand: Clarify Kconfig entry MTD_NAND

MTD_NAND is large and encloses much more than what the symbol is
actually used for: raw NAND. Clarify the symbol by naming it
MTD_RAW_NAND instead.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

powerpc/86xx: Add support for Emerson/Artesyn MVME7100

Add support for the Artesyn MVME7100 Single Board Computer.

The MVME7100 is a 6U form factor VME64 computer with:

- A two e600 cores Freescale MPC8641D CPU
- 2 GB of DDR2 onboard memory
- Four Gigabit Ethernets
- Five 16550 compatible UARTs
- One USB 2.0 port
- Two PCI/PCI eXpress Mezzanine Card (PMC/XMC) Slots
- A DS1375 Real Time Clock (RTC)
- 512 KB of Non-Volatile Memory (NVRAM)
- Two 64 KB EEPROMs
- 128 MB NOR and 4/8 GB NAND Flash

This patch is based on linux-4.7-rc1 and has been only boot tested.

Limitations:
This patch covers only models 171 and 173
No plans to support CPLD timers

Know issues:
All four PHYs work in polling mode

Configuration is missing for:
PCI IDSEL and PCI Interrupt definition

Support is missing for:
Cache and memory controllers (which are very similar to the 85xx ones
but right now I don't know if we can re-use their support)
Watchdog, USB, NVRAM, NOR, NAND, EEPROMs, VME, PMC/XMC and RTC

Signed-off-by: Alessio Igor Bogani <alessio.bogani@elettra.eu>
Signed-off-by: Scott Wood <oss@buserror.net>

powerpc/86xx: Switch to kconfig fragments approach

Signed-off-by: Alessio Igor Bogani <alessio.bogani@elettra.eu>
Signed-off-by: Scott Wood <oss@buserror.net>