crypto: ARM assembler SHA1 code incompatible with THUMB2_KERNEL

The "optimized" ARM assembler code for SHA1 is not Thumb2 compatible, and the
CPUs the optimizations are intended for do not support Thumb2 anyway, so it
makes no sense to make it compatible. Just don't allow it to be selected if
we're building a Thumb2 kernel.

Signed-off-by: Matt Sealey <matt@genesi-usa.com>
Commit 68b2532 (ARM: imx: select HAVE_IMX_SRC when SMP is enabled)
introduces a build error with imx_v6_v7_defconfig when CONFIG_SMP is
deselected.

  LINK    vmlinux
  LD      vmlinux.o
  MODPOST vmlinux.o
  GEN     .version
  CHK     include/generated/compile.h
  UPD     include/generated/compile.h
  CC      init/version.o
  LD      init/built-in.o
arch/arm/mach-imx/built-in.o: In function `imx6q_restart':
platform-ahci-imx.c:(.text+0x448c): undefined reference to `imx_src_prepare_restart'
arch/arm/mach-imx/built-in.o: In function `imx6q_pm_enter':
platform-ahci-imx.c:(.text+0x4544): undefined reference to `imx_set_cpu_jump'
arch/arm/mach-imx/built-in.o: In function `imx6q_init_irq':
platform-ahci-imx.c:(.init.text+0xbef0): undefined reference to `imx_src_init'
make[1]: *** [vmlinux] Error 1

While the commit adds 'def_bool y if SMP' for HAVE_IMX_SRC, it should
not remove 'select HAVE_IMX_SRC' from SOC_IMX6Q, as the IMX6Q UP build
also needs HAVE_IMX_SRC.  Add the HAVE_IMX_SRC select back for SOC_IMX6Q
to fix above build error.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>