ARM: mvebu: Warn about memory chunks too small for DDR training

ARM: mvebu: Warn about memory chunks too small for DDR training

For each memory region the first 10K are reserved for DDR training. Emit
a warning if the area happens to be smaller than these 10K. This should
not happen, but if it does this message simplifies diagnosing the
problem.

This fixes a W=1 compiler error:

	arch/arm/mach-mvebu/board-v7.c: In function ‘mvebu_scan_mem’:
	arch/arm/mach-mvebu/board-v7.c:84:27: error: variable ‘size’ set but not used [-Werror=unused-but-set-variable]
	   84 |                 u64 base, size;
	      |                           ^~~~

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>