firmware: ti_sci: fix strncat length check
gcc-7 notices that the length we pass to strncat is wrong:
drivers/firmware/ti_sci.c: In function 'ti_sci_probe':
drivers/firmware/ti_sci.c:204:32: error: specified bound 50 equals the size of the destination [-Werror=stringop-overflow=]
Instead of the total length, we must pass the length of the
remaining space here.
Fixes: 580c229f1b6f ("firmware: Add basic support for TI System Control Interface (TI-SCI) protocol")
Cc: stable@vger.kernel.org
Acked-by: Nishanth Menon <nm@ti.com>
Acked-by: Santosh Shilimkar <ssantosh@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>