x86/cpu: Add a helper function x86_read_arch_cap_msr()

x86/cpu: Add a helper function x86_read_arch_cap_msr()

BugLink: https://bugs.launchpad.net/bugs/1852338
commit 286836a70433fb64131d2590f4bf512097c255e1 upstream.

Add a helper function to read the IA32_ARCH_CAPABILITIES MSR.

Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Neelima Krishnan <neelima.krishnan@intel.com>
Reviewed-by: Mark Gross <mgross@linux.intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Connor Kuehl <connor.kuehl@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>