x86: apic - unify clear_local_APIC

- Remove redundant masking of APIC_LVTTHMR register in apic_32.c

- Add masking of APIC_LVTTHMR register to apic_64.c. We use a bit
  complicated #ifdef here: CONFIG_X86_MCE_P4THERMAL is 32bit specific
  and X86_MCE_INTEL is 64bit specific so the appropriate config variable
  will be set by Kconfig.

- the APIC_ESR register clearing in apic_64.c now uses not straightforward
  way but this is allowed tradeoff.

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>