ACPI: battery: fix ACPI battery technology reporting

At least some systems report technology information with trailing spaces:

{pts/1}% cat -E /var/tmp/bat/2.6.23 | grep type
battery type:            Li-ION  $

Use strncasecmp to compare model string to skip trailing part

Signed-off-by: Andrey Borzenkov <arvidjaar@mail.ru>
Acked-by: Alexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>