fs/kernel_read_file: Remove FIRMWARE_EFI_EMBEDDED enum

fs/kernel_read_file: Remove FIRMWARE_EFI_EMBEDDED enum

The "FIRMWARE_EFI_EMBEDDED" enum is a "where", not a "what". It
should not be distinguished separately from just "FIRMWARE", as this
confuses the LSMs about what is being loaded. Additionally, there was
no actual validation of the firmware contents happening.

Fixes: e4c2c0ff00ec ("firmware: Add new platform fallback mechanism and firmware_request_platform()")
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Acked-by: Scott Branden <scott.branden@broadcom.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20201002173828.2099543-3-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>