fix the following warning:
chip/sam_allocateheap.c:120:8: warning: #warning "CONFIG_MM_REGIONS < 3: NFC SRAM not included in HEAP" [-Wcpp]
120 | # warning "CONFIG_MM_REGIONS < 3: NFC SRAM not included in HEAP"
| ^~~~~~~
chip/lpc17_40_allocateheap.c:176:6: warning: #warning "CONFIG_MM_REGIONS > 1: This configuration has no available AHB SRAM Bank0/1" [-Wcpp]
176 | # warning "CONFIG_MM_REGIONS > 1: This configuration has no available AHB SRAM Bank0/1"
| ^~~~~~~
chip/stm32l4_allocateheap.c:141:4: warning: #warning "CONFIG_MM_REGIONS large enough but I do not know what some of the region(s) are" [-Wcpp]
141 | # warning "CONFIG_MM_REGIONS large enough but I do not know what some of the region(s) are"
| ^~~~~~~
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>