eficonfig: menu-driven addition of UEFI boot option

This commit add the "eficonfig" command.
The "eficonfig" command implements the menu-driven UEFI boot option
maintenance feature. This commit implements the addition of
new boot option. User can select the block device volume having
efi_simple_file_system_protocol and select the file corresponding
to the Boot#### variable. User can also enter the description and
optional_data of the BOOT#### variable in utf8.

This commit adds "include/efi_config.h", it contains the common
definition to be used from other menus such as UEFI Secure Boot
key management.

Signed-off-by: Masahisa Kojima <masahisa.kojima@linaro.org>
diff --git a/cmd/Kconfig b/cmd/Kconfig
index 67c7d25..ea506a0 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -1928,6 +1928,13 @@
 	  particularly for managing boot parameters as  well as examining
 	  various EFI status for debugging.
 
+config CMD_EFICONFIG
+	bool "eficonfig - provide menu-driven uefi variables maintenance interface"
+	depends on CMD_BOOTEFI_BOOTMGR
+	help
+	  Enable the 'eficonfig' command which provides the menu-driven UEFI
+	  variable maintenance interface.
+
 config CMD_EXCEPTION
 	bool "exception - raise exception"
 	depends on ARM || RISCV || SANDBOX || X86