staging: mt7621-pci: remove [ASSERT|DEASSERT]_SYSRST_PCIE macros

Driver is using reset_control kernel API's to manage this so this
two macros are not needed anymore. Remove them.

Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>