MIPS: MSP71xx: Fix build error.

  CC      arch/mips/pmc-sierra/msp71xx/msp_irq.o
/home/ralf/src/linux/linux-mips/arch/mips/pmc-sierra/msp71xx/msp_irq.c:112:2: error: request for member ‘flags’ in something not a structure or union
/home/ralf/src/linux/linux-mips/arch/mips/pmc-sierra/msp71xx/msp_irq.c:118:2: error: request for member ‘flags’ in something not a structure or union
make[4]: *** [arch/mips/pmc-sierra/msp71xx/msp_irq.o] Error 1

caused by 57336bc1056798d89714b7fb1b1d197e6bda6819 [MIPS: Mark cascade and
low level interrupts IRQF_NO_THREAD].

Commas to separate struct initializers generally are considered useful to
enhance the compilation experience of the user.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>