mfd: tps65090: MFD_TPS65090 needs to select REGMAP_IRQ

This fixes below build error:

drivers/built-in.o: In function `tps65090_i2c_probe':
drivers/mfd/tps65090.c:180: undefined reference to `regmap_add_irq_chip'
drivers/mfd/tps65090.c:190: undefined reference to `regmap_irq_chip_get_base'
drivers/mfd/tps65090.c:203: undefined reference to `regmap_del_irq_chip'
drivers/built-in.o: In function `tps65090_i2c_remove':
drivers/mfd/tps65090.c:213: undefined reference to `regmap_del_irq_chip'
make: *** [vmlinux] Error 1

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>