configs: mt7988: move image load address to 0x44000000

This patch sets mt7988 image load address to 0x44000000 to support loading
larger images.

diff --git a/configs/mt7988_rfb_defconfig b/configs/mt7988_rfb_defconfig
index 4d7454d..eebf7fb 100644
--- a/configs/mt7988_rfb_defconfig
+++ b/configs/mt7988_rfb_defconfig
@@ -7,7 +7,7 @@
 CONFIG_NR_DRAM_BANKS=1
 CONFIG_DEFAULT_DEVICE_TREE="mt7988-rfb"
 CONFIG_TARGET_MT7988=y
-CONFIG_SYS_LOAD_ADDR=0x46000000
+CONFIG_SYS_LOAD_ADDR=0x44000000
 CONFIG_DEBUG_UART_BASE=0x11000000
 CONFIG_DEBUG_UART_CLOCK=40000000
 CONFIG_DEBUG_UART=y