staging: fix dt3155 build

When the dt3155 driver is built-in (not as a loadable module),
these build errors happen:

  drivers/staging/dt3155/dt3155_drv.c:1047: error: implicit declaration of function 'request_irq'
  drivers/staging/dt3155/dt3155_drv.c:1048: error: 'IRQF_SHARED' undeclared (first use in this function)
  drivers/staging/dt3155/dt3155_drv.c:1048: error: 'IRQF_DISABLED' undeclared (first use in this function)
  drivers/staging/dt3155/dt3155_drv.c:1091: error: implicit declaration of function 'free_irq'

so remove the #ifdef MODULE check since it's not needed.  Also remove
the CONFIG_PCI check since the Kconfig file already requires that.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Scott Smedley <ss@aao.gov.au>
Tested-by: Jan III Sobieski <jan3sobi3ski@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>