checkpatch: fix USLEEP_RANGE test

checkpatch: fix USLEEP_RANGE test

Do not test udelay() for a value less than 10usec when passed a variable
instead of a hard-coded number; there is no way for checkpatch to know the
value of the variable.  As it is today, it will complain about variables
with alphanumeric characters plus '_', e.g.  foo_bar, but not variables
with other characters, eg.  foo->bar.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>