arm32: Fix relocation of env_addr if POSITION_INDEPENDENT=y

Apply commit 534f0fbd6520 ("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>
diff --git a/arch/arm/lib/crt0.S b/arch/arm/lib/crt0.S
index 6d566dc..a031143 100644
--- a/arch/arm/lib/crt0.S
+++ b/arch/arm/lib/crt0.S
@@ -147,6 +147,11 @@
 	ldr	r1, =CONFIG_TEXT_BASE
 	sub	r1, r0
 	add	lr, r1
+#if defined(CONFIG_SYS_RELOC_GD_ENV_ADDR)
+	ldr	r0, [r9, #GD_ENV_ADDR]		/* r0 = gd->env_addr */
+	add	r0, r0, r1
+	str	r0, [r9, #GD_ENV_ADDR]
+#endif
 #endif
 	ldr	r0, [r9, #GD_RELOC_OFF]		/* r0 = gd->reloc_off */
 	add	lr, lr, r0