target-ppc: fix LPCR SPR number

PowerISA defines LPCR SPR number as 318=0x13E but QEMU uses the value of
316.

This fixes the definition of LPCR SPR.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Alexander Graf <agraf@suse.de>
target-ppc: remove powerpc 970gx

The 970GX definition was added in 2007 and it made sense then but this
version has never been released to the markets and it does not exist in
the real world so there is no point in emulating it.

This removes 970GX.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Alexander Graf <agraf@suse.de>
target-ppc: fix SPR_CTRL/SPR_UCTRL register numbers

Assuming that "U" in SPR_UCTRL is for "user", there is inconsistency with
970 user manuals/P5-bookIV/PowerISA204 which define the number as:

                       priviledged
#   spr5-9 spr0-4 name mtspr mfspr len cat
136 00100  01000  CTRL   -    no    32  S
152 00100  11000  CTRL  yes    -    32  S

This swaps the numbers. No effect from this change is expected though.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Alexander Graf <agraf@suse.de>
target-ppc: remove embedded MMU SPRs from 970, P5+/7/7+/8

PowerISA 2.04+ puts MMUCFG and MMUCSR0 SPRs to "E" (embedded) category so
remove it from POWER7/8 class as it is "S" (server) category.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Alexander Graf <agraf@suse.de>
target-ppc: remove unsupported SPRs from 970 and P5+

SPR_750FX_HID2 and L2CR are not defined in 970* user manuals nor POWER5
bookIV nor PowerISA 2.04, the numbers assigned to them are not defined
either so remove them.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Alexander Graf <agraf@suse.de>