x86/intel_rdt: Making CBM name and type more explicit

cbm_validate() receives a pointer to the variable that will be initialized
with a validated capacity bitmask. The pointer points to a variable of type
unsigned long that is immediately assigned to a variable of type u32 by the
caller on return from cbm_validate().

Let cbm_validate() initialize a variable of type u32 directly.

At this time also change tha variable name "data" within parse_cbm() to a
name more reflective of the content: "cbm_val". This frees up the generic
"data" to be used later when it is indeed used for a collection of input.

Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: fenghua.yu@intel.com
Cc: tony.luck@intel.com
Cc: vikas.shivappa@linux.intel.com
Cc: gavin.hindman@intel.com
Cc: jithu.joseph@intel.com
Cc: dave.hansen@intel.com
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/5e29cf0209ea2deac9beacd35cbe5239a50959fb.1529706536.git.reinette.chatre@intel.com