rtlwifi: rtl8188ee: enable MSI interrupts mode

Some HP notebooks using this rtl8188ee hardware module can't get
AP scan results with pin-based interrupts mode, enabling MSI interrupts
mode could fix it.

As RealTek's testing results, RTL8188EE works well with both MSI mode
and pin-based mode fallback.

Signed-off-by: Adam Lee <adam.lee@canonical.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>