mips: Add generic test defconfig for qemu

Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>

arch/mips/configs/malta_qemu_32r2_defconfig

+CONFIG_MIPS_MALTA=y
+CONFIG_CPU_LITTLE_ENDIAN=y
+CONFIG_CPU_MIPS32_R2=y
+CONFIG_MIPS_MT_SMP=y
+CONFIG_NR_CPUS=2
+CONFIG_SYSVIPC=y
+CONFIG_HIGH_RES_TIMERS=y
+CONFIG_MODULES=y
+CONFIG_MODULE_UNLOAD=y
+CONFIG_PCI=y
+CONFIG_NET=y
+CONFIG_PACKET=y
+CONFIG_UNIX=y
+CONFIG_INET=y
+CONFIG_IDE=y
+CONFIG_BLK_DEV_IDECD=y
+CONFIG_IDE_GENERIC=y
+CONFIG_BLK_DEV_GENERIC=y
+CONFIG_BLK_DEV_PIIX=y
+CONFIG_NETDEVICES=y
+CONFIG_PCNET32=y
+CONFIG_INPUT_EVDEV=y
+CONFIG_SERIAL_8250=y
+CONFIG_SERIAL_8250_CONSOLE=y
+CONFIG_FB=y
+CONFIG_FB_CIRRUS=y
+CONFIG_USB=y
+CONFIG_USB_UHCI_HCD=y
+CONFIG_EXT4_FS=y
+CONFIG_TMPFS=y
+CONFIG_TMPFS_POSIX_ACL=y
+CONFIG_DEVTMPFS=y
+CONFIG_DEVTMPFS_MOUNT=y