PCI: dra7xx: Remove unneeded use of IS_ERR_VALUE()

There is no need to use the IS_ERR_VALUE() macro for checking the return
value from pm_runtime_* functions.

Test for a negative pm_runtime_get_sync() return value instead of using
IS_ERR_VALUE().

The semantic patch that makes this change is available in
scripts/coccinelle/api/pm_runtime.cocci.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: Kishon Vijay Abraham I <kishon@ti.com>