sh: add defconfig for J-Core J2

This defconfig is intended not to be specific to a particular board;
it enables drivers for all currently-supported hardware, and should be
updated to include additional drivers as they are added.
Signed-off-by: NRich Felker <dalias@libc.org>

arch/sh/configs/j2_defconfig

+CONFIG_SMP=y
+CONFIG_SYSVIPC=y
+CONFIG_POSIX_MQUEUE=y
+CONFIG_NO_HZ=y
+CONFIG_HIGH_RES_TIMERS=y
+CONFIG_CPU_SUBTYPE_J2=y
+CONFIG_MEMORY_START=0x10000000
+CONFIG_MEMORY_SIZE=0x04000000
+CONFIG_CPU_BIG_ENDIAN=y
+CONFIG_SH_DEVICE_TREE=y
+CONFIG_HZ_100=y
+CONFIG_CMDLINE_OVERWRITE=y
+CONFIG_CMDLINE="console=ttyUL0 earlycon"
+CONFIG_BINFMT_ELF_FDPIC=y
+CONFIG_BINFMT_FLAT=y
+CONFIG_NET=y
+CONFIG_PACKET=y
+CONFIG_UNIX=y
+CONFIG_INET=y
+CONFIG_DEVTMPFS=y
+CONFIG_DEVTMPFS_MOUNT=y
+CONFIG_NETDEVICES=y
+CONFIG_SERIAL_UARTLITE=y
+CONFIG_SERIAL_UARTLITE_CONSOLE=y
+CONFIG_I2C=y
+CONFIG_SPI=y
+CONFIG_SPI_JCORE=y
+CONFIG_WATCHDOG=y
+CONFIG_MMC=y
+CONFIG_MMC_SPI=y
+CONFIG_CLKSRC_JCORE_PIT=y
+CONFIG_JCORE_AIC=y
+CONFIG_EXT4_FS=y
+CONFIG_VFAT_FS=y
+CONFIG_FAT_DEFAULT_IOCHARSET="ascii"
+CONFIG_FAT_DEFAULT_UTF8=y
+CONFIG_NLS_DEFAULT="utf8"
+CONFIG_NLS_CODEPAGE_437=y
+CONFIG_NLS_ASCII=y
+CONFIG_NLS_UTF8=y