arm32: Fix relocation of env_addr if POSITION_INDEPENDENT=y

Apply commit 534f0fbd ("arm64: Fix relocation of env_addr if
POSITION_INDEPENDENT=y") also for 32-bit ARM.

This change fixes crashing of U-Boot on ARMv7 (Omap3 / Cortex-A8) Nokia N900
phone (real HW). Note that qemu emulator of this board with same u-boot.bin
binary has not triggered this crash.

Crash happened after U-Boot printed following debug lines to serial console:

    initcall: 0001ea8c (relocated to 8fe0aa8c)
    Loading Environment from <NULL>... Using default environment
    Destroy Hash Table: 8fe25a98 table = 00000000
    Create Hash Table: N=387

Signed-off-by: Pali Rohár <pali@kernel.org>