x86: samus: Increase the pre-reloc memory again

This is again too small, so increase it slightly.
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

configs/chromebook_samus_defconfig

 CONFIG_X86=y
 CONFIG_SYS_TEXT_BASE=0xFFE00000
-CONFIG_SYS_MALLOC_F_LEN=0x1c00
+CONFIG_SYS_MALLOC_F_LEN=0x1d00
 CONFIG_DEBUG_UART_BOARD_INIT=y
 CONFIG_DEBUG_UART_BASE=0x3f8
 CONFIG_DEBUG_UART_CLOCK=1843200