Start using the arm_reg_current() call.  This shrinks and speeds
the affected code.  It can also prevent some coredumps coming from
invalid CPSR values ... the ARMV4_5_CORE_REG_MODE() macro returns
bogus registers if e.g. "Secure Monitor" mode isn't supported by
the current CPU.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>