accel/habanalabs/gaudi2: Fix incorrect string length computation in gaudi2_psoc_razwi_get_engines()
snprintf() returns the "number of characters which *would* be generated for
the given input", not the size *really* generated.
In order to avoid too large values for 'str_size' (and potential negative
values for "PSOC_RAZWI_ENG_STR_SIZE - str_size") use scnprintf()
instead of snprintf().