Corrected stack vs hart_stack_size assertion

For example:

4 cores, each with 1KB hart_stack_size, should be able to fit a stack
with a size of 4KB exactly. I.e 4 = (3 + 1) * 1

Author: janderholm

riscv-rt/link.x.in

@@ -218,7 +218,7 @@ ASSERT(_stext + SIZEOF(.text) < ORIGIN(REGION_TEXT) + LENGTH(REGION_TEXT), "
 ERROR(riscv-rt): The .text section must be placed inside the REGION_TEXT region.
 Set _stext to an address smaller than 'ORIGIN(REGION_TEXT) + LENGTH(REGION_TEXT)'");
 
-ASSERT(SIZEOF(.stack) > (_max_hart_id + 1) * _hart_stack_size, "
+ASSERT(SIZEOF(.stack) >= (_max_hart_id + 1) * _hart_stack_size, "
 ERROR(riscv-rt): .stack section is too small for allocating stacks for all the harts.
 Consider changing `_max_hart_id` or `_hart_stack_size`.");