lib/bitmap.c: quiet sparse noise about address space

__bitmap_parse() and __bitmap_parselist() both take a pointer to a kernel
buffer as a parameter and then cast it to a pointer to user buffer for use
in cases when the parameter is_user indicates that the buffer is actually
located in user space.  This casting, and the casts in the callers,
results in sparse noise like the following:

	warning: incorrect type in initializer (different address spaces)
	  expected char const [noderef] <asn:1>*ubuf
	  got char const *buf
	warning: cast removes address space of expression

Since these casts are intentional, use __force to quiet the noise.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>