MIPS: configs: lb60: Fix defconfig not selecting correct board

Since INGENIC_GENERIC_BOARD was introduced, the JZ4740_QI_LB60 option
is no longer the default, so the symbol has to be selected by the
defconfig, otherwise the kernel built will be for a generic Ingenic
board and won't have the Device Tree blob built-in.

Cc: stable@vger.kernel.org # v5.7
Fixes: 6224920 ("MIPS: ingenic: Default to a generic board")
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

arch/mips/configs/qi_lb60_defconfig

@@ -8,6 +8,7 @@ CONFIG_EMBEDDED=y
 # CONFIG_COMPAT_BRK is not set
 CONFIG_SLAB=y
 CONFIG_MACH_INGENIC=y
+CONFIG_JZ4740_QI_LB60=y
 CONFIG_HZ_100=y
 # CONFIG_SECCOMP is not set
 CONFIG_MODULES=y