This can help find unused symbols. Those end up without a type if
'default' is used instead of 'def_bool', which generates a warning.
Search for "Kconfig.defconfig" in
https://docs.zephyrproject.org/latest/application/kconfig-tips.html for
a longer explanation.
Keep the 'def_bool' for the following symbols, which seem to be
deliberately defined only in Kconfig.defconfig files:
- ALTERA_AVALON_I2C
- ALTERA_AVALON_MSGDMA
- ALTERA_AVALON_PIO
- ALTERA_AVALON_QSPI
- ALTERA_AVALON_SYSID
- CLOCK_CONTROL_IMX_CCM
- CPU_EM4_DMIPS
- CPU_EM4_FPUDA
- CPU_EM4_FPUS
- FP_FPU_DA
- I2C_GECKO
Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
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