memory: tegra: Do not ask for IRQ sharing

Memory Controller driver never shared IRQ with any other driver and very
unlikely that it will. Hence there is no need to request IRQ sharing and
the corresponding flag can be dropped safely.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>