OMAP3: PM: fix lockdep warning caused by omap3_pm_init

OMAP3: PM: fix lockdep warning caused by omap3_pm_init

This patch uses kmalloc(size,GFP_ATOMIC) instead of kmalloc(size,GFP_KERNEL)
to allocate memory for instance of struct power_state in pwrdms_setup(),
since it may be called by pwrdm_for_each() with irq disabled.

It is a easy fix for the following lockdep warning caused by
kmalloc(size,GFP_KERNEL) in pwrdms_setup():

Power Management for TI OMAP3.
------------[ cut here ]------------
WARNING: at kernel/lockdep.c:2282 lockdep_trace_alloc+0xe8/0xfc()
Modules linked in:
[<c0032ccc>] (unwind_backtrace+0x0/0xec) from [<c0056934>] (warn_slowpath_common+0x48/0x60)
[<c0056934>] (warn_slowpath_common+0x48/0x60) from [<c007da10>] (lockdep_trace_alloc+0xe8/0xfc)
[<c007da10>] (lockdep_trace_alloc+0xe8/0xfc) from [<c00cd9bc>] (kmem_cache_alloc+0x28/0x178)
[<c00cd9bc>] (kmem_cache_alloc+0x28/0x178) from [<c000f184>] (pwrdms_setup+0x30/0xf8)
[<c000f184>] (pwrdms_setup+0x30/0xf8) from [<c00381c4>] (pwrdm_for_each+0x64/0x84)
[<c00381c4>] (pwrdm_for_each+0x64/0x84) from [<c000ef60>] (omap3_pm_init+0x3f4/0x5ac)
[<c000ef60>] (omap3_pm_init+0x3f4/0x5ac) from [<c002c2c0>] (do_one_initcall+0x30/0x1d4)
[<c002c2c0>] (do_one_initcall+0x30/0x1d4) from [<c00088d8>] (kernel_init+0xa4/0x118)
[<c00088d8>] (kernel_init+0xa4/0x118) from [<c002ddf8>] (kernel_thread_exit+0x0/0x8)
---[ end trace 1e06f8d97dc5a19b ]---

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>