ARM: 7206/1: Add generic ARM instruction set condition code checks.

This patch breaks the ARM condition checking code out of nwfpe/fpopcode.{ch}
into a standalone file for opcode operations. It also modifies the code
somewhat for coding style adherence, and adds some temporary variables for
increased readability.

Signed-off-by: Leif Lindholm <leif.lindholm@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>