x86/RAS: Simplify SMCA HWID descriptor struct

Call it simply smca_hwid and call local variables "hwid". More readable.

Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Yazen Ghannam <yazen.ghannam@amd.com>
Link: http://lkml.kernel.org/r/20161103125556.15482-2-bp@alien8.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>