lib: Rewrite qemu-armv7 ramdetect

* Move armv7 RAM dection to a common place
* Enable it for all emulated platforms
* Use 32bit probe values and restore memory even on failure
* Use the new logic on the following boards:
** qemu-armv7
** qemu-riscv

Tested on qemu-system-riscv:
Fixes kernel panic due to wrong memory limits reported.

Change-Id: I37386c6a95bfc3b7b25aeae32c6e14cff9913513
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/33934
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

src/soc/ucb/riscv/cbmem.c

@@ -12,16 +12,10 @@
  */
 
 #include <cbmem.h>
+#include <symbols.h>
+#include <ramdetect.h>
 
 void *cbmem_top(void)
 {
-	uintptr_t base;
-	size_t size;
-
-	/* Use dummy values until we can query the memory size again */
-	//query_mem(configstring(), &base, &size);
-	base = 0x80000000;
-	size = 128 * MiB;
-
-	return (void *)(base + size);
+	return _dram + (probe_ramsize((uintptr_t)_dram, CONFIG_DRAM_SIZE_MB) * MiB);
 }