crypto: omap-sham - Use pm_runtime_irq_safe()

omap_sham_handle_queue() can be called as part of done_task tasklet.
During this its atomic and any calls to pm functions cannot sleep.

But there is a call to pm_runtime_get_sync() (which can sleep) in
omap_sham_handle_queue(), because of which the following appears:
" [  116.169969] BUG: scheduling while atomic: kworker/0:2/2676/0x00000100"

Add pm_runtime_irq_safe() to avoid this.

Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>