plat/arm/sgi: Use NT_FW_CONFIG instead of HW_CONFIG

BL31: Use helper function to save registers in SMC handler

Change copyright guidelines

MMC init check and STM32MP1 MMC driver improvements

With the two new APIs 'plat_arm_sgi_get_platform_id' and
'plat_arm_sgi_get_config_id' that are available now, BL31 need not
depend on hw_config device tree to identify the platform. In addition
to this, the existing hardware description in hw_config can be limited
to use by BL33 and not by the operating system.

So the hardware description from hw_config dts can be moved into
nt_fw_config dts and the use of hw_config dts can be removed.

Change-Id: I873b7e1e72823d3ec5d253a848e85ae724f09e49
Signed-off-by: Chandni Cherukuri <chandni.cherukuri@arm.com>

tzc380: Fix some asserts

This driver can be compiled in release builds, but GCC generates warnings
for some comparisons and that prevents the firmware from being built in
debug builds.

Change-Id: Ic52e1b4a11896ecf086864fbe2b5bfc143ec9b1b
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

Use the helper function `save_gp_registers` to save the register
state to cpu_context on entry to EL3 in SMC handler. This has the
effect of saving x0 - x3 as well into the cpu_context which was
not done previously but it unifies the register save sequence
in BL31.

Change-Id: I5753c942263a5f9178deda3dba896e3220f3dd83
Signed-off-by: Soby Mathew <soby.mathew@arm.com>

Add NXP i.MX8MQ basic support