x86: Add msr command

It is useful to obtain the results of MSR queries as well as to update
MSR registers, so add a command these tasks.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/cmd/x86/Makefile b/cmd/x86/Makefile
index 1648907..9252152 100644
--- a/cmd/x86/Makefile
+++ b/cmd/x86/Makefile
@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0+
 
 obj-$(CONFIG_CMD_CBSYSINFO) += cbsysinfo.o
-obj-y += cpuid.o mtrr.o
+obj-y += cpuid.o msr.o mtrr.o
 obj-$(CONFIG_CMD_EXCEPTION) += exception.o
 obj-$(CONFIG_USE_HOB) += hob.o
 obj-$(CONFIG_HAVE_FSP) += fsp.o