efi: ESRT creation tests

efi: ESRT creation tests

This commmit exercises the ESRT creation in a EFI selftest.

 A fake FMP, with TEST_ESRT_NUM_ENTRIES FW images, is installed in the
 system leading to the corresponding ESRT entries being populated.
 The ESRT entries are checked against the datastructure used to
 initialize the FMP.

Invocation from the sandbox platform:
add to sandbox_defconfig:
  +CONFIG_CMD_BOOTEFI_SELFTEST=y

 make sandbox_capsule_defconfig all
 ./u-boot -d arch/sandbox/dts/test.dtb
 bootefi selftest

CC: Heinrich Schuchardt	<xypron.glpk@gmx.de>
CC: Sughosh Ganu <sughosh.ganu@linaro.org>
CC: AKASHI Takahiro <takahiro.akashi@linaro.org>
CC: Ilias Apalodimas <ilias.apalodimas@linaro.org>
CC: Andre Przywara <andre.przywara@arm.com>
CC: Alexander Graf <agraf@csgraf.de>
CC: nd@arm.com
Signed-off-by: Jose Marinho <jose.marinho@arm.com>
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>