KVM: PPC: E500: Fail init when not on e500v2

KVM: PPC: E500: Fail init when not on e500v2

When enabling the current KVM code on e500mc, I get the following oops:

    Oops: Exception in kernel mode, sig: 4 [#1]
    SMP NR_CPUS=8 P2041 RDB
    Modules linked in:
    NIP: c067df4c LR: c067df44 CTR: 00000000
    REGS: ee055ed0 TRAP: 0700   Not tainted  (3.2.0-10391-g36c5afe)
    MSR: 00029002 <CE,EE,ME>  CR: 24042022  XER: 00000000
    TASK = ee0429b0[1] 'swapper/0' THREAD: ee054000 CPU: 2
    GPR00: c067df44 ee055f80 ee0429b0 00000000 00000058 0000003f ee211600 60c6b864
    GPR08: 7cc903a6 0000002c 00000000 00000001 44042082 2d180088 00000000 00000000
    GPR16: c0000a00 00000014 3fffffff 03fe9000 00000015 7ff3be68 c06e0000 00000000
    GPR24: 00000000 00000000 00001720 c067df1c c06e0000 00000000 ee054000 c06ab51c
    NIP [c067df4c] kvmppc_e500_init+0x30/0xf8
    LR [c067df44] kvmppc_e500_init+0x28/0xf8
    Call Trace:
    [ee055f80] [c067df44] kvmppc_e500_init+0x28/0xf8 (unreliable)
    [ee055fb0] [c0001d30] do_one_initcall+0x50/0x1f0
    [ee055fe0] [c06721dc] kernel_init+0xa4/0x14c
    [ee055ff0] [c000e910] kernel_thread+0x4c/0x68
    Instruction dump:
    9421ffd0 7c0802a6 93410018 9361001c 90010034 93810020 93a10024 93c10028
    93e1002c 4bfffe7d 2c030000 408200a4 <7c1082a6> 90010008 7c1182a6 9001000c
    ---[ end trace b8ef4903fcbf9dd3 ]---

Since it doesn't make sense to run the init function on any non-supported
platform, we can just call our "is this platform supported?" function and
bail out of init() if it's not.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>