imx: Kconfig: Add HAS_CAAM option

Currently CONFIG_SECURE_BOOT is selecting FSL_CAAM for all i.MX devices,
this causes the following error when building mx6sl boards since
this SoC doesn't have the CAAM block:

In file included from drivers/crypto/fsl/jobdesc.c:12:0:
drivers/crypto/fsl/jobdesc.c: In function 'inline_cnstr_jobdesc_blob_dek':
include/fsl_sec.h:268:25: error: 'CAAM_ARB_BASE_ADDR' undeclared (first use
in this function)
 #define SEC_MEM_PAGE1  (CAAM_ARB_BASE_ADDR + 0x1000)
                         ^
drivers/crypto/fsl/jobdesc.c:140:21: note: in expansion of macro 'SEC_MEM_PAGE1'
  memcpy((uint32_t *)SEC_MEM_PAGE1, (uint32_t *)plain_txt, in_sz);
                     ^
include/fsl_sec.h:268:25: note: each undeclared identifier is reported only
once for each function it appears in
 #define SEC_MEM_PAGE1  (CAAM_ARB_BASE_ADDR + 0x1000)
                         ^
drivers/crypto/fsl/jobdesc.c:140:21: note: in expansion of macro 'SEC_MEM_PAGE1'
  memcpy((uint32_t *)SEC_MEM_PAGE1, (uint32_t *)plain_txt, in_sz);
                     ^
scripts/Makefile.build:280: recipe for target 'drivers/crypto/fsl/jobdesc.o'
failed
make[3]: *** [drivers/crypto/fsl/jobdesc.o] Error 1
scripts/Makefile.build:425: recipe for target 'drivers/crypto/fsl' failed
make[2]: *** [drivers/crypto/fsl] Error 2
scripts/Makefile.build:425: recipe for target 'drivers/crypto' failed
make[1]: *** [drivers/crypto] Error 2

Add HAS_CAAM configuration to avoid this error.

Signed-off-by: Breno Lima <breno.lima@nxp.com>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
diff --git a/arch/arm/mach-imx/mx7/Kconfig b/arch/arm/mach-imx/mx7/Kconfig
index 365501d..4f8b4e1 100644
--- a/arch/arm/mach-imx/mx7/Kconfig
+++ b/arch/arm/mach-imx/mx7/Kconfig
@@ -10,6 +10,7 @@
 	default y
 
 config MX7D
+	select HAS_CAAM
 	select ROM_UNIFIED_SECTIONS
 	imply CMD_FUSE
 	bool