x86/mtrr: Have only one set_mtrr() variant

Today there are two variants of set_mtrr(): one calling stop_machine()
and one calling stop_machine_cpuslocked().

The first one (set_mtrr()) has only one caller, and this caller is
running only when resuming from suspend when the interrupts are still
off and only one CPU is active. Additionally this code is used only on
rather old 32-bit CPUs not supporting SMP.

For these reasons the first variant can be replaced by a simple call of
mtrr_if->set().

Rename the second variant set_mtrr_cpuslocked() to set_mtrr() now that
there is only one variant left, in order to have a shorter function
name.

Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20230502120931.20719-8-jgross@suse.com


Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>