IB/ipath: Build IBA7220 code unconditionally

The new IBA7220 code added a call to ipath_init_iba7220_funcs() that
is compiled unconditionally, but only built the IBA7220 code if
PCI_MSI is enabled.  Fix this by building the IBA7220 file
unconditonally.

This fixes build breakage when PCI_MSI=n, HT_IRQ=y and
INFINIBAND_IPATH=y reported by Ingo Molnar <mingo@elte.hu>:

 drivers/built-in.o: In function `ipath_init_one':
 ipath_driver.c:(.devinit.text+0x1e5bc): undefined reference to `ipath_init_iba7220_funcs'

Signed-off-by: Roland Dreier <rolandd@cisco.com>