Fix efivar-libs dependency

- Some arches do not have efivar-libs, so let's require it
  conditionally.

keylime.spec

@@ -1,5 +1,10 @@
 %global srcname keylime
 
+# efivar-libs is only available on these arches.
+%ifarch x86_64 aarch64
+%global have_efivar 1
+%endif
+
 Name:    keylime
 Version: 6.4.2
 Release: %autorelease
@@ -53,11 +58,14 @@ License: MIT
 Conflicts: keylime < 6.3.0-3
 
 Requires(pre): shadow-utils
-Requires: efivar-libs
 Requires: procps-ng
 Requires: tpm2-tss
 Requires: tpm2-tools
 
+%if 0%{?have_efivar}
+Requires: efivar-libs
+%endif
+
 
 %description base
 The base package contains the Keylime default configuration