[nrf fromtree] soc: nordic: poweroff: remove disabling of emul l05/l10 unused RAM

Code is now incorporated into SystemInit() function of MDK 8.69.1,
which is integrated within nrfx 3.10.0.

Signed-off-by: Nikodem Kastelik <[email protected]>
(cherry picked from commit 8b495dc)

Author: nika-nordic

soc/nordic/common/poweroff.c

@@ -50,14 +50,6 @@ void z_sys_poweroff(void)
 
 	/* Disable retention for all memory blocks */
 	nrfx_ram_ctrl_retention_enable_set(ram_start, ram_size, false);
-#if defined(DEVELOP_IN_NRF54L15) && defined(NRF54L05_XXAA)
-	nrf_memconf_ramblock_ret_mask_enable_set(NRF_MEMCONF, 0, 0x1F8, false);
-	nrf_memconf_ramblock_ret2_mask_enable_set(NRF_MEMCONF, 0, 0x1F8, false);
-#endif
-#if defined(DEVELOP_IN_NRF54L15) && defined(NRF54L10_XXAA)
-	nrf_memconf_ramblock_ret_mask_enable_set(NRF_MEMCONF, 0, 0x1C0, false);
-	nrf_memconf_ramblock_ret2_mask_enable_set(NRF_MEMCONF, 0, 0x1C0, false);
-#endif
 
 #endif /* defined(CONFIG_HAS_NORDIC_RAM_CTRL) */