lmb: arm: Increase LMB alignment to 16k in arch_lmb_reserve_generic()

According to input NXP, the 4k alignment is not always sufficient.
Currently iMX works around this problem by implementing board specific
LMB reservation, however it is likely this could also occur on other
systems. Increase the LMB reservation alignment to 16k by default.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Alexey Brodkin <alexey.brodkin@synopsys.com>
Cc: Angelo Dureghello <angelo@sysam.it>
Cc: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Cc: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Cc: Hai Pham <hai.pham.ud@renesas.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
Cc: Tom Rini <trini@konsulko.com>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Ye Li <ye.li@nxp.com>
Reviewed-by: Tom Rini <trini@konsulko.com>

arch/arm/lib/stack.c

@@ -45,5 +45,5 @@ static ulong get_sp(void)
 
 void arch_lmb_reserve(struct lmb *lmb)
 {
-	arch_lmb_reserve_generic(lmb, get_sp(), gd->ram_top, 4096);
+	arch_lmb_reserve_generic(lmb, get_sp(), gd->ram_top, 16384);
 }