soc: arm: stm32: Remove mem pool selection

Since the use of kmalloc was removed from the DMAMUX driver
there is no need for a memory pool anymore.

Signed-off-by: Erwin Rol <[email protected]>

Author: lowlander

soc/arm/st_stm32/common/Kconfig.defconfig.series

@@ -75,10 +75,6 @@ if DMA
 config DMA_STM32
 	default y
 
-config HEAP_MEM_POOL_SIZE
-	default 1024
-	depends on DMAMUX_STM32
-
 endif # DMA
 
 config MEMC_STM32