__copy_to/from_user_inatomic should call __copy_to/from_user
because there is not necessary to check access because of kernel function.

might_sleep in copy_to/from_user macros is causing problems
in debug sessions too (CONFIG_DEBUG_SPINLOCK_SLEEP).

BUG: sleeping function called from invalid context at
.../arch/microblaze/include/asm/uaccess.h:388
in_atomic(): 1, irqs_disabled(): 0, pid: 1, name: swapper
1 lock held by swapper/1:
 #0:  (&p->cred_guard_mutex){......}, at: [<c00d4b90>] prepare_bprm_creds+0x2c/0x88
Kernel Stack:
...

Call Trace:
[<c0006bd4>] microblaze_unwind+0x7c/0x94
[<c0006684>] show_stack+0xf4/0x190
[<c0006730>] dump_stack+0x10/0x30
[<c00103a0>] __might_sleep+0x12c/0x160
[<c0090de4>] file_read_actor+0x1d8/0x2a8
[<c0091568>] generic_file_aio_read+0x6b4/0xa64
[<c00cd778>] do_sync_read+0xac/0x110
[<c00ce254>] vfs_read+0xc8/0x160
[<c00d585c>] kernel_read+0x38/0x64
[<c00d5984>] prepare_binprm+0xfc/0x130
[<c00d6430>] do_execve+0x228/0x370
[<c000614c>] microblaze_execve+0x58/0xa4

caused by file_read_actor (mm/filemap.c) which calls
__copy_to_user_inatomic.

Signed-off-by: Michal Simek <monstr@monstr.eu>