env: Rename getenv/_f() to env_get()

We are now using an env_ prefix for environment functions. Rename these
two functions for consistency. Also add function comments in common.h.

Quite a few places use getenv() in a condition context, provoking a
warning from checkpatch. These are fixed up in this patch also.

Suggested-by: Wolfgang Denk <wd@denx.de>
Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/powerpc/cpu/mpc85xx/cpu_init.c b/arch/powerpc/cpu/mpc85xx/cpu_init.c
index a3076d8..ea46e49 100644
--- a/arch/powerpc/cpu/mpc85xx/cpu_init.c
+++ b/arch/powerpc/cpu/mpc85xx/cpu_init.c
@@ -256,7 +256,7 @@
 	 * is not setup properly yet. Search for tdm entry in
 	 * hwconfig.
 	 */
-	ret = getenv_f("hwconfig", buffer, sizeof(buffer));
+	ret = env_get_f("hwconfig", buffer, sizeof(buffer));
 	if (ret > 0) {
 		tdm_hwconfig_enabled = hwconfig_f("tdm", buffer);
 		/* If tdm is defined in hwconfig, set law for tdm workaround */
@@ -280,7 +280,7 @@
 	cpc_corenet_t *cpc = (cpc_corenet_t *)CONFIG_SYS_FSL_CPC_ADDR;
 
 	/* Extract hwconfig from environment */
-	ret = getenv_f("hwconfig", buffer, sizeof(buffer));
+	ret = env_get_f("hwconfig", buffer, sizeof(buffer));
 	if (ret > 0) {
 		/*
 		 * If "en_cpc" is not defined in hwconfig then by default all
@@ -754,7 +754,7 @@
 	char *buf = NULL;
 	int n, res;
 
-	n = getenv_f("hwconfig", buffer, sizeof(buffer));
+	n = env_get_f("hwconfig", buffer, sizeof(buffer));
 	if (n > 0)
 		buf = buffer;
 
@@ -794,7 +794,7 @@
 #endif
 
 #if defined(CONFIG_PPC_SPINTABLE_COMPATIBLE) && defined(CONFIG_MP)
-	spin = getenv("spin_table_compat");
+	spin = env_get("spin_table_compat");
 	if (spin && (*spin == 'n'))
 		spin_table_compat = 0;
 	else
@@ -845,7 +845,7 @@
 #ifdef CONFIG_SYS_SRIO
 	srio_init();
 #ifdef CONFIG_SRIO_PCIE_BOOT_MASTER
-	char *s = getenv("bootmaster");
+	char *s = env_get("bootmaster");
 	if (s) {
 		if (!strcmp(s, "SRIO1")) {
 			srio_boot_master(1);