ARM: entry-common: get rid of unnecessary ifdefs

The contents of the asm_trace_hardirqs_on is already conditional on
CONFIG_TRACE_IRQFLAGS.  There's little point also making the use
of the macro conditional as well.  Get rid of these ifdefs to make
the code easier to read.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>