arm: am57xx: Allow bootm to load larger kernels

linux-mainline with multi_v7_defconfig + Android configs takes more
space than regular TI Android kernel and bootm will fail to load it.
Let's increase max kernel size up to 64 MiB to make it possible to run
such kernel.

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Reviewed-by: Igor Opaniuk <igor.opaniuk@gmail.com>
Reviewed-by: Lokesh Vutla <lokeshvutla@ti.com>
diff --git a/include/configs/am57xx_evm.h b/include/configs/am57xx_evm.h
index e69e800..45fd218 100644
--- a/include/configs/am57xx_evm.h
+++ b/include/configs/am57xx_evm.h
@@ -22,6 +22,8 @@
 #define CONFIG_ENV_OFFSET_REDUND	(CONFIG_ENV_OFFSET + CONFIG_ENV_SIZE)
 #define CONFIG_SYS_REDUNDAND_ENVIRONMENT
 
+#define CONFIG_SYS_BOOTM_LEN		SZ_64M
+
 #define CONSOLEDEV			"ttyO2"
 #define CONFIG_SYS_NS16550_COM1		UART1_BASE	/* Base EVM has UART0 */
 #define CONFIG_SYS_NS16550_COM2		UART2_BASE	/* UART2 */