crypto: omap-des - Fix "schedule while atomic" bug

When using DES module the next bug appears:

    BUG: scheduling while atomic: kworker/0:1/63/0x00000102

With backtrace as follows:

<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< cut here >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

[<c0012294>] (dump_backtrace) from [<c00124ac>] (show_stack+0x18/0x1c)
[<c0012494>] (show_stack) from [<c0752554>] (dump_stack+0x84/0xc4)
[<c07524d0>] (dump_stack) from [<c0750218>] (__schedule_bug+0x54/0x64)
[<c07501c4>] (__schedule_bug) from [<c07548a4>] (__schedule+0x4ac/0x53c)
[<c07543f8>] (__schedule) from [<c075496c>] (schedule+0x38/0x88)
[<c0754934>] (schedule) from [<c03c3984>] (rpm_resume+0x158/0x59c)
[<c03c382c>] (rpm_resume) from [<c03c3e1c>] (__pm_runtime_resume+0x54/0x6c)
[<c03c3dc8>] (__pm_runtime_resume) from [<c0568ff8>] (omap_des_handle_queue+0x154/0x7bc)
[<c0568ea4>] (omap_des_handle_queue) from [<c05696b8>] (omap_des_crypt+0x58/0xbc)
[<c0569660>] (omap_des_crypt) from [<c0569730>] (omap_des_cbc_decrypt+0x14/0x18)
[<c056971c>] (omap_des_cbc_decrypt) from [<c0297534>] (authenc_verify_ahash_done+0xe0/0xe8)
[<c0297454>] (authenc_verify_ahash_done) from [<c056a330>] (omap_sham_finish_req+0x58/0xa8)
[<c056a2d8>] (omap_sham_finish_req) from [<c056b714>] (omap_sham_done_task+0x1c0/0x1e0)
[<c056b554>] (omap_sham_done_task) from [<c003e53c>] (tasklet_action+0x80/0x118)
[<c003e4bc>] (tasklet_action) from [<c003e740>] (__do_softirq+0x11c/0x260)
[<c003e624>] (__do_softirq) from [<c003eb64>] (irq_exit+0xc0/0xfc)
[<c003eaa4>] (irq_exit) from [<c000f1c4>] (handle_IRQ+0x4c/0x98)
[<c000f178>] (handle_IRQ) from [<c0008568>] (gic_handle_irq+0x34/0x64)
[<c0008534>] (gic_handle_irq) from [<c0758540>] (__irq_svc+0x40/0x70)

<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< cut here >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Insight was seen in drivers/crypto/omap-sham.c driver.
All credits for this patch go to Grygorii Strashko.

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>