Fix issue in Floating point register restore
Fix issue in Floating point register restore

The `fpregs_context_restore()` function used to restore the floating point
regsiter context had a typo error wherein it was doing `str` instead of
`ldr` for a register. This issue remained undetected becuase none of the ARM
Standard development platforms save and restore the floating point register
context when a context switch is done. This patch corrects the issue.

Change-Id: Id178e0ba254a5e0a4a844f54b39d71dc34e0f6ea

sandrine-bailleux/arm-trusted-firmware,achingupta/arm-trusted-firmware,sandrine-bailleux-arm/arm-trusted-firmware,sbranden/arm-trusted-firmware,davwan01/arm-trusted-firmware,achingupta/arm-trusted-firmware,sandrine-bailleux-arm/arm-trusted-firmware,sandrine-bailleux/arm-trusted-firmware,lsigithub/arm-trusted-firmware_public,lsigithub/arm-trusted-firmware_public,sbranden/arm-trusted-firmware,davwan01/arm-trusted-firmware