powerpc: Don't use alloc_bootmem() in init_IRQ() path

This patch fixes various badnesses like this for all interrupt
controllers:

------------[ cut here ]------------
Badness at c04db9dc [verbose debug info unavailable]
NIP: c04db9dc LR: c04db9ac CTR: 00000000
REGS: c053de30 TRAP: 0700   Not tainted  (2.6.31-rc1-00432-ge69b2b5-dirty)
MSR: 00021000 <ME,CE>  CR: 22020084  XER: 00000000
TASK = c0500480[0] 'swapper' THREAD: c053c000
GPR00: 00000001 c053dee0 c0500480 00000000 00000050 00000020 3fffffff 00000000
GPR08: 00000001 c0540000 e0080080 00000000 22000084 64183600 3ff8f800 00000000
GPR16: 841b0240 449a0303 00000000 00000000 00000000 00000000 00000000 c04f5bf4
GPR24: 00000000 00000000 00000000 00000050 00000020 00000000 3fffffff 00000050
NIP [c04db9dc] alloc_arch_preferred_bootmem+0x48/0x74
LR [c04db9ac] alloc_arch_preferred_bootmem+0x18/0x74
Call Trace:
[c053dee0] [c000a5a4] __of_address_to_resource+0x44/0xd0 (unreliable)
[c053def0] [c04dba58] ___alloc_bootmem_nopanic+0x50/0x108
[c053df20] [c04dbb28] ___alloc_bootmem+0x18/0x50
[c053df30] [c04d5de0] qe_ic_init+0x5c/0x1b0
[c053df70] [c04d77b0] mpc85xx_mds_pic_init+0xb8/0x10c
[c053dfb0] [c04cf374] init_IRQ+0x28/0x3c

p.s. commit 85355bb272db31a3f2dd99d547eef794805e1319 ("powerpc: Fix
mpic alloc warning") missed some alloc_bootmem() instances, this is
now fixed.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Acked-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>