locking/x86: Use named operands in rwsem.h

Since GCC version 3.1 it is possible to specify input and output
operands using symbolic names, which can be referenced within the
assembler code.

Converting to named operands makes it easier to understand and maintain
the code in the future.

Update operands in asm/rwsem.h accordingly.

Signed-off-by: Miguel Bernal Marin <miguel.bernal.marin@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170925230349.18834-1-miguel.bernal.marin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>