change(linker): enlarge the RAM size for riscv64 targets to support release mode builds

crates/eonix_hal/src/arch/riscv64/memory.x

@@ -2,10 +2,10 @@ OUTPUT_ARCH(riscv)
 ENTRY(_start)
 
 MEMORY {
-    RAM    : org = 0x0000000080200000, len = 4M
+    RAM    : org = 0x0000000080200000, len = 8M
     VDSO   : org = 0x00007f0000000000, len = 4K
     KBSS   : org = 0xffffffff40000000, len = 2M
-    KIMAGE : org = 0xffffffff80200000, len = 2M
+    KIMAGE : org = 0xffffffff80200000, len = 8M
 }
 
 REGION_ALIAS("REGION_TEXT", KIMAGE);