fix(brcm): add braces around bodies of conditionals

fix(brcm): add braces around bodies of conditionals

On release builds EMMC_TRACE doesn't expand to anything. Some
conditionals with no braces end up with empty bodies. This produces a
warning when compiling with -Werror=empty-body (enabled by -Wextra).

Since TF-A coding guidelines require braces to comply with MISRA
guidelines anyway, add them in the whole file.

Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
Change-Id: Ib4e691efc7acdb8fb8692278c7a9772fc894f77f