target-ppc: Extract aliases from definitions list

Move definitions that were 100% identical except for the name into a
list of aliases so that we don't register duplicate CPU types.

We need to support recursive lookup due to code names referencing a
generic name referencing a specific model revision.

Signed-off-by: Andreas Färber <afaerber@suse.de>
target-ppc: Make -cpu "ppc" an alias to "ppc32"

Drop the #if 0'ed alternative to make it "ppc64" for TARGET_PPC64.
If we ever want to change it, we can more easily do so now.

Signed-off-by: Andreas Färber <afaerber@suse.de>
target-ppc: Extract MPC5xx aliases

Their PVR differed but was defined to MPC5xx.

Signed-off-by: Andreas Färber <afaerber@suse.de>
target-ppc: Extract MPC8xx as aliases

They used different PVRs but were defined to MPC8xx.

Signed-off-by: Andreas Färber <afaerber@suse.de>
target-ppc: Extract 40x aliases

Signed-off-by: Andreas Färber <afaerber@suse.de>
target-ppc: Extract 440 aliases

Signed-off-by: Andreas Färber <afaerber@suse.de>
target-ppc: Extract ppc32 and ppc64 CPUs as aliases

Signed-off-by: Andreas Färber <afaerber@suse.de>
target-ppc: Convert CPU definitions (WIP)

Signed-off-by: Andreas Färber <afaerber@suse.de>
target-ppc: Extract 74x7[A] aliases

Signed-off-by: Andreas Färber <afaerber@suse.de>
target-ppc: Extract 74x5 as aliases

Signed-off-by: Andreas Färber <afaerber@suse.de>
target-ppc: Extract 74x1 aliases

Signed-off-by: Andreas Färber <afaerber@suse.de>
target-ppc: Extract alias for 7450

Signed-off-by: Andreas Färber <afaerber@suse.de>
target-ppc: Extract 7448 alias

Signed-off-by: Andreas Färber <afaerber@suse.de>
target-ppc: Extract 7410 alias

Signed-off-by: Andreas Färber <afaerber@suse.de>
target-ppc: 7400

Signed-off-by: Andreas Färber <afaerber@suse.de>
target-ppc: 7x5

Signed-off-by: Andreas Färber <afaerber@suse.de>
target-ppc: 750L

Signed-off-by: Andreas Färber <afaerber@suse.de>
750gx

Signed-off-by: Andreas Färber <afaerber@suse.de>
750fx

Signed-off-by: Andreas Färber <afaerber@suse.de>
750cxe

Signed-off-by: Andreas Färber <afaerber@suse.de>