Add possibility to encrypt BL* firmware and some code fixes

This MR contains changes which adding the encryption of BL* firmware.

requested review from @jani

assigned to @AGnau

@iopsys-platform FYI

added 15 commits

• 1cf43614...20abfdf6 - 9 commits from branch devel
• 262a63d0 - iopsys-common: Fix impossible to choose from menuconfig config
• 5fca9059 - iopsys-common: Add secure boot configs for fw encryption
• 5520dc82 - iopsys-common: Merge config type with prompt in secure boot KConfig
• 26968adc - iopsys-common: Use choice instead of string for SB configs
• 9f73f713 - airoha: Add fw encryption
• d1442c0c - airoha: Surround the whole secure boot makefile by main condition

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added 21 commits

• d1442c0c...0dd303c6 - 20 commits from branch devel
• 72e87452 - airoha: Add fw encryption

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resolved all threads

changed the description

removed review request for @jani

added 4 commits

• 72e87452...6dcfe553 - 3 commits from branch devel
• d498b891 - airoha: Add fw encryption

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marked this merge request as ready

closed